Hi, I'm Sora and I'm here to help you get all of the achievements in Otaku's Adventure. I have a lot of free time... Also, if this is not the first English guide, or I'm violating some copyright laws or other issues, please pm me and I'll remove this guide. (Hopefully this doesn't happen it took me almost a week to make this). Please enjoy the rest of the guide.
Ps. Please have a go yourself first obviously... It is an amazingly hilarious and fun experience.

Start the game by pressing on New Game. Your name doesn't have an effect on the overall game-play, but your birth date does. So please either put in something you can remember or your own birth date. The birth date is for needed for the first achievement. Now you are set to start the game. Achievements are not in any order, just how I made it...
Warning: Spoilers ahead... Duh...

The start of the game is straight forward, it is a short tutorial sequence.

Achievement 1: Figure Master.
You wake up and have to turn off the Air conditioner (AC).
Before leaving your room to head to the Bathroom, you collect one item; the tissue box.
This item is located on the sliding compartment of the shelf to the left.
Before advancing, you can do two things.
You can also, grab the phone early, it is under the pillow. (Preparation for Achievement 2).
Click on the tissue box, then click on the tissue part 20 times, to receive the Head part A for the Figure. (There are 6 in total; this is the first achievement I mentioned before).
Before leaving click on the red bucket next to the toilet to pick up Head part F.
Click inside of the laundry machine to pick up the third piece; Head part E.
Under the Tv is Head part C.
Click on the cushion to pick up the Head part D.
Lucky last piece for the head is in the green box on the table.
This is where your birth date, the one you put for your character comes in; told you it was important.
Once you enter in your birth date, month then day, the box opens and it contains Head part B.
Click on one of the head pieces on the side and drag another piece on top of it, this should start the mini-game to assemble the head.
First drag part E; the small round ball, to Part D; the back of the helmet.
Grab part A; the face, and drag to part E.
Drag part B; the front of the helmet, to the rest of the head.
Place part F; the V, on the top of the helmet.
Finally part C; red thingy to on top of the part F.
Head back to your bedroom and place the bad boy on to the figure on the top left shelf.
Done Achievement 1.

Achievement 2: Game Master.
This is the second achievement; to complete the mini-game without taking damage.
Find the phone, like I mentioned before it is under your pillow in your room.
Click on your phone, then click on the cat icon for a mini-game to appear.
It is relatively simple if you have played bullet hell styled games before.
You shoot one pellet/bullet at a constant rate, this can be used to destroy enemies, but doesn't work on the big spikes.
You start off with 2 hearts.
The are "enemies" just floating faces, hearts and stuff. Note: Hearts damage you too so don't touch those sneaky hearts...
The big spikes floating around too.
Almost forgot the most important part, click and hold on your cat avatar to move around. Near the end there is a boss which is a giant face which fills up the right side of the screen. It shoots multiple waves of pellets/bullets at a time.
If you manage to get pass that damage-less, then you have unlock the second achievement.
Done Achievement 2.

Achievement 3: No Leak.
You move out to your living room, but you can't interact with anything until you go to the Bathroom first.
The bathroom is located to the top left of your screen.
Click and hold on the toilet to take a leak. Note: I'd suggest you save before trying this mini-game, it is rather tricky; the achievement is to take a leak without missing.
When you click on the toilet a yellow bar on the side indicates the amount of urine.
The yellow arrow on the bottom, which is spastically moving side to side is what you have to aim to take the leak.
So, when you think it is in the middle, click and hold down, if no leak, keep holding, achievement get. If you miss, keep taking a leak, wipe your mess then load and retry.
Done Achievement 3.

Achievement 4: Loyal Fan.
After the too realistic date, *cough cough* I mean the failed date with Mei Mei, you go to the convenience store to get yourself a pick me up, a bottle of water.
Your budget is $200.
The Yamashita Magazine is $100.
Note: Grab the water bottle, only $5. (For the next Achievement). Buy the walkthrough too, $50. (For another Achievement). Total of $155, if you grab additionally items.
Purchase that item, click on it and boom easiest achievement yet.
Ps. Can it get any easier??
Done Achievement 4.

Achievement 5: Guru Guru.
Drink the water...
Ps. Yes it can...
Achievement 5 done.

Achievement 6: Perfect Victory.
Note: Save before trying.
Use the walkthrough to make it possible to beat the girl, Gohard (LOVE HER NAME <3, by the way). Still has a relatively normal levelled difficulty.
Now you just have to 3 - 0 her in a game of Pong.
Achievement 6 Done.

Achievement 7: Bobo's Playground
This is one of the long and tricky ones.
Note: You might want to start a new save or load up one that starts just after you leave Mei Mei and enter the convenience store.
You need the water bottle and the Kio OST from the convenience store ($25). Note: You have to either go on the "date" with Gohard (Still love her name) or save Waifu. Otherwise you will be forever alone... To "date" Gohard (<3) you have to get the walkthrough in the convenience store ($50). To save Waifu, you have to choose the push her option.
Move onto the arcade sequence.
You will need three coins (four, if you want to do Achievement 7 and 8 together) click on the head of the boy with grey hair, the one closest to you.
There should be a coin lodged in his hair, if not try the others.
The second coin is in the box on the floor.
Pick up the stool before heading up to see the Michael
Give him water, place the stool underneath the AC, next to the washing machines.
Investigate the AC, and grab the tool, give it to Michael for the third coin.
Now this is for the fourth coin (If you want to prepare for achievement 8), it is in the book to the right of your screen. (To the left of Michael from his perspective).
Please use the walkthrough item before attempting this mini-game. It will make your life a lot easier.
Use two coins to play a game with Gohard (<3).
Then, move to Bobo's house.
After you drink the tea, save your game (for Achievement 8).
You will fall asleep at 100.
Now what you want to do is:
Put the the game coin into the Gachapon on the table to the left of the couch, which will give you another coin.
Put in the coin from the Gachapon to get a "Thank you for Playing" note. -15 sleepiness.
Play the Kio's OST. -15 sleepiness.
Go to the right hallway, the left door, should be locked. Click on the key-hole area, when it zooms in try to insert your house keys, the key breaks. -15 sleepiness.
Click on the fish tank, drag power bank to it. + 10 sleepiness
Get the floppy disk (resume) in the fridge and the Lunch box (bento) in the lower compartment of the fridge.
Microwave the Bento. +10 sleepiness. Ps. Microwave the phone after the Bento. -15 sleepiness.
Go to the toilet, click on the toilet brush to play the toilet cleaning mini-game. +40 sleepiness. P.s. Use the cloth and brush to clean the toilet.
On the wall of the right hallway, there is a blank frame. Paint on the blank frame hanging on the wall. +40 sleepiness
The door on the right leads to Bobo's room. Break all of Bobo's figures, click on each one until they break. +40 sleepiness.
Finally, go onto his PC, insert the floppy disk and modify the resume. +40 sleepiness.
Once all of these steps are finished, you should unlock it.
Ps. I used the Chinese guide as a reference (Hope you don't mind... I used google translate, only the sleepiness points made sense).
Achievement 7 done.

Achievement 8: Take Medicine and Sleep Well.
Reload the save file for Bobo's house and put the coin into the Gachapon machine, until you get the sleeping pill.
Click on it in the side bar, and eat it. +999 sleepiness.
Achievement 8 done.

Sorry about the split, there is an annoying text limitation to each section apparently. Anyways...

Achievement 9: Focus Wrong.
Note: I recommend you save.
Save Waifu for the first time (from the lightbulb).
Then protect her from the shady guy (By pretending to be a girl...?).
Then in the first screen of the shooting game there is a cardboard box (Bottom right-hand side).
You need to shoot this 30 times without dying, before you move on to the next section.
Shoot the box when there are not shady dudes, and if there are shady dudes, kill them rinse and repeat till it is unlocked.
P.s. The sexy gun has an infinite magazine size, so no need to worry about running out of bullets, also, no need to reload. "...just hit your mouse like a mini-gun."
Achievement 9 done.

Achievement 10: Shooting King.
Note: Save when the narrator comes out in the part where you are trying to protect Waifu from the Shady dude. Also, save in between the three shooting fights.
There are 3 sections. Ps. Avoid the pedestrians, and the cat during the second fight is annoying... the third fight; the boss fight, has you shooting his nut when exposed and baby versions of himself.
The first one is really long. It is until after you fall off the cliff riding the motorcycle. (Achievements 11 and 12 can be done in the part after the fall).
Second one is not as long. (Achievement 13 is before this part).
The third one is the boss. (Achievement 15 can be unlocked after this fight).
If done correctly and damage-less, should have unlocked the achievement.
Achievement 10 done.

Achievement 11: Great Eyes and Hands.
Note: Save before attempting the mini-game.
You should be in the Abandoned Hospital for this Achievement.
Leave the room Waifu is in.
Pick up the Remote, which is next to the Tv.
Go downstairs to pick up the long metal bar to the bottom right of the screen (Iron Pipe).
Go upstairs, there should be two doorways on the right. Click on the left doorway to get to the upper floor of the hospital, where the wall is knocked down. Click on the tree to get the single leaf (Mulberry Leaf).
Go back into the previous room and use the right doorway. Use the grinder (Whetstone) to change the Iron Pipe into a needle, by dragging the Pipe to the Whetstone.
Feed the Mulberry Leaf to the Silk worm that is on the railing near the sink, inside the metal box.
Use remote to fast-forward the worm. (This is hilarious, maybe my sense of humour is bad...).
Now remember to save, otherwise you have to do everything from the last save point, which is not that bad, but we need to save the frames.
Click on the needle, and drag the thread (Silk Thread) to it to start the mini-game.
Ps. You get the needle and thread from this (Used in Achievement 12).
If you do it successfully on the first try…
Achievement 11 done.

Achievement 12: Perfect Surgery.
Note: Save as this part is long. Save again before the surgery as well.
In Achievement 11 you get the Needle and Thread. However, I will assume you do not have the Needle and Thread.
Medical Alcohol is in the same room as Waifu on the floor, in front of the two beds.
Go downstairs to grab the Red Card. Located left of the stairs.
Pick up the long metal bar to the bottom right of the screen (Iron Pipe).
Go back up the stairs.
Pick up the Remote, which is next to the Tv.
Grab the loudspeaker (Loudencer) in the left cardboard box.
Grab the Blue Card in the right cardboard box.
Attach the Loudencer to the Sexy Gun.
Drag the Loud, Sexy, Gun to left side of the screen where the Glass Box is to shatter the Glass Box to get the Syringe inside.
Now go up the stairs to the third floor.
Open the metal drawers on the third floor, open the top one to read a Book about cards. The Book also contains the Yellow Card. On the right-hand of the book, in the pages.
Open the bottom drawer to get a Magic Box (Magical Material).
Get the scalpel by entering the directional code into the elevator buttons.
The pattern is found in the skeleton's eye, next to the elevator.
The pattern it up, up, down, down, up and down.
You get the scalpel from Eason, the Medical Supreme. Also, grab the Red Hammer (Lifting Jack) in the room to the left. The one with the steps for the surgery on the wall.
Go to the left room on floor 3, the room with the big wall is broken down.
Click on the tree to get the single leaf (Mulberry Leaf).
To the right of the Scissors, there is a gap where you can place the Lifting Jack to lift the rock and get the Scissors.
Then you will automatically use the scissors to cut your T-Shirt to make Bandages.
Go to the room through the bottom right doorway to use the Magic Combining Machine Thingy.
Insert the yellow card in the left compartment and the Magical Material in the right compartment and then click the red OK to create the A Key.
Use the grinder (Whetstone), next to the Magic Combining Machine Thingy, to change the Iron Pipe into a needle, by dragging the Pipe to the Whetstone.
Feed the Mulberry Leaf to the Silk worm that is on the railing near the sink, inside the small metal box. Use remote to fast-forward the worm. (This is still hilarious to me, sorry for bad humour...).
Click on the needle, and drag the Silk Thread to the Needle to start the mini-game. Now you have the Needle and Thread.
Anesthetic is in the Metal Safe, in the same room as Waifu, opened by the A Key. the Metal Safe, also, contains the Green Card.
Drag the Anesthetic to the Syringe to get the Anesthetic Needle.
Now using the green card and the A Key in the Magic Combining Machine Thingy you get the Tweezers.

Return to Waifu and attempt the surgery. Remember to save beforehand.
Helpful tip: It might help to order your Inventory.
The procedure is Medical Alcohol, Anesthetic Needle, Scalpel, Tweezers, Needle and Thread and Bandages. Ps. Does not need to be done relatively quickly, just before your nose bleeds too much. There is a red bar on top left hand corner to indicate this.
If no mistakes occur then...
Ps. Rumour has it, not that I have tried, cough cough, but you can shoot Waifu during the surgery. It does not help her, at all.
Achievement 12 done.

Achievement 13: One Shoot One Catch.
Note: Save before the mini-game.
After going to the mysterious Island, click on the yellow arrow to go left click on the hole to pick up the Telescopic Gun.
Then click on the left yellow arrow again.
This will show a tree with a shady dude sleeping underneath it.
In the tree there is an item stuck.
Drag the telescopic gun to it to start the mini-game.
If you miss reload and try again if not…
Achievement 13 done.

Achievement 14: Piercing Eye.
Note: Save before the event.
During the comic event, which you start, by beating Gohard (Still love her name <3, sorry I know I'm annoying I'll stop... you probably stopped reading already... I'm just wasting my time...). Ps. the walkthrough from the convenience store is necessary for this.
You go through the dialogue, the green dude goes into the VIP room, but it's too dark to see, use the External Flashlight that Gohard (Love her nam... cough cough) hands you.
Be ready as you can only use it once (I don't know if it is a bug, but mine only works once and then disappears).
See any part of his body click on it. Ps. The flash of light only remains for a second or two then it becomes pitch darkness again.
If done on the first try the achievement should unlock.
Achievement 14 done.

The annoying text limitation again...

Achievement 15: Boxing King
Note: Save before you start the fight, save after each fight if uninjured.
There are 4 alians, no wait 3, no no no 3.5. Ps. The game refers to Aliens as Alians, it’s not my spelling.
I’ll explain why it’s 3.5 in a minute.
After defeating the first alian, it turns out to have just been a body controlled by the second alian, therefore the .5 of an alian.
So for the first alian, defend the first attack immediate as you see the alian’s arm move, then you can counterattack.
The second alien, has a move pattern of finger flick and bite.
The finger flick move has a second delay, so wait for a second before blocking, and attack the moment it opens it’s big mouth.
For the next alian you do nothing, otherwise, if you attack or defend you get hurt.
The three-eye octopus monster, the first stage, the left and right first tentacle, defend then counterattack, for the other right tentacle it attacks slow, wait a moment then block before counterattacking.
In the second phase the octopus throws rocks with a delay, wait till it stops shaking the rock then defend, but don’t attack it because you have to use it to block the laser after the rock.
If no damage was taken then you should have unlocked it.
Achievement 15 done.

Achievement 16: Perfect Flight
Note: Save before starting the engine of the spaceship.
Complete the flight mini-game, somewhat like the Cat mini-game, but no bullets and no boss.
Avoid the debris as you fly through space, before arriving on another alian planet.
If no damage was taken then...
Achievement 16 done.

Achievement 17: Michael's Secret.
Start Michael's favour, by giving him the water bottle to drink.
Grab the stool downstairs.
Then place it next to the washing machine to investigate the AC to get the flat screwdriver. Ps. You need the golden screwdriver from the convenience store for $160 to finish this achievement.
Go to the broken arcade machine and then click on the coin slot.
Use the golden screwdriver to unscrew one of the plus screws and then swap by dragging the flat screwdriver to the golden screwdriver.
Then unscrew the rest of the screws.
Install your power bank to the middle.
Go up stairs to Michael.
He will then tell you his secret. (Prepares for Achievement 18). Ps. All of the achievements that mention another world is started from this point.
Achievement 17 done.

Achievement 18: Legend of the Strongest Hero.
Note: Save after going to the another world and before the fight.
Michael teleports you to another world.
You farm up coins by defeating monster random encountered as you walk around (not in towns though).
Go to a vending machine to get level up cans. P.s. The levelling up cans for levels 3 to 5 are unlocked when you get to the tent on the other side of the map.
Start from level 2 cans working up to level 5 cans for all characters.
You drag the cans to the character on the tablet given to you by (´･ω･`).
Once all of your characters in your party are level 5, head to the forest across the bridge. (On the far right).
Shout out, to get the first hero to appear.
Beat him with your level 5 characters.
Achievement 18 done.

Achievement 19: Wedding.
To get this achievement you have to have done Michael's Secret Achievement.
Michael teleports you to another world.
There you will be able to fight monster to get coins.
You can use the coins to buy items for your house. Ps. In total, all items cost $2300.
Once you get enough coins and buy all of the items for the house.
Go into your house and you get the option to marry (´･ω･`).
At this point you have already got the achievement.
Achievement 19 done.

Achievement 20: Precious Stuff.
You need to get up to the Inverted Castle. For that you need to beat the boss in the Tall/High Tower, for his Sword Artefact.
Once you get this sword, go to the Inverted Castle to cut down the wall to enter.
After you defeat the Bat should be relatively easy, talk to him, and he talk about the Strong Pill.
You need to get the Strong Pill from the Physical Village.
You can get the Strong Pill and the Chemist.
Go back give the Strong Pill to the Bat.
Take the Book Props on the bottom shelf.
Then go to the top floor, place the book prop on the floor to get take the vacuum cleaner. Ps. Make sure to pick the Book Prop again.
Click on the Vacuum Cleaner to obtain the inner part of the Vacuum, then again to the innermost part then again to get the Dirty Ball.
Then go to the middle floor.
Activate the water fountain by using the switch on the right side.
Drag the mud block into the water to get the key.
Open the locked door, place the Book Prop under the side cabinet before opening it, then you can catch takes the flashlight so it doesn't break.
Achievement 20 done.

Achievement 21: RPG Master.
You can use my other money guide to get enough money to buy enough levelling up cans to level up all characters to level 5. Ps. There are 5 characters, (´･ω･`), Super Rookie, Physicsist, Chemist and You.
Find the Super Rookie in Rookie village, Physicsist and the Chemist in the Physical VIllage and you start off with (´･ω･`) and yourself. Ps. Physicsist costs 100, for first joining your party, then double of the initial cost, after each time he leaves your party. Also, the Chemist is unlocked later in the story. Check on Achievement 20 to see how he is unlocked.

Hi, again...

Achievement 22: Invincible.
Defeat all 7 bosses.
The Possessed Swordsman (Evil Blade Saint) who drops the sword artefact is in the Tall/High Tower.
He has high evade, but doesn't have that high hp so can be killed if he doesn't evade in a matter of turns.
He will use Evil Spirit for the first three turns, which will cause your characters to have their turned skipped.
P.s. He can't avoid poison bottles.
The Fungus that drops the Growth Cell is under the Toe Mountain.
You get poisoned from physical attacks.
Try using skills to avoid getting poisoned.
The Big Snake gives access to the Portal door, leading to a Tv and Game Console. It is above the Toe Mountain, a giant cylinder.
Puts Hunter Tag on a character, meaning that character is going to be attacked. So focus healing on that character.
Also, has a Flame Breather AOE which the damage is split for even if the hunter tag is active.
The Bat Queen that drops the Guitar is in the Inverted Castle. Ps. Can't enter without the Sword Artefact.
The queen has a move to avoid all attacks for one turn, by jumping up really high.
She also gets the bat we made strong with the pill to fight for her. The Betrayal... It hits...
Bai WuChang and Hei WuChang drops the Revive Barrel (needed for the Achievement 25), is at the cemetery. Ps. Can't do without the Guitar Artefact.
For all of the other bosses you can just find them, for this boss you need to kill your main character, you can use poison, bought from the vending machine for 40 gold.
Play the guitar at the cemetery to fight the boss.
There are two, Bai WuChang and Hei WuChang.
I recommend killing Bai WuChang, the white one, as he can revive Hei WuChang, when he dies.
Hei WuChang, to my experience, only uses an AOE move called Grip Grip Grip.
The First Hero is at the Dark Forest above the Inverted Castle.
He has a variety of moves.
Otaku Glow, halves the hp of your character.
Meatball Explorer, steals consumable items from your inventory, including poison.
AOE Silence, lasts one turn Silencing all of your characters.
Magic Burn, deals the same amount of damage it takes mp for. Ps. It takes 90 mp, and if you don't have 90 it deals the amount it took.
Ps. You can farm this boss for money... (Check out my other guide).
The Final boss is located in a Game Cartridge.
Has an Energy Shield absorbs up to 1000 damage.
Shoots and AOE laser beam.
Spike attack which stacks damage the time the character is hit.
Ps. Level of the bosses are scaled to yours. You can one-shot all of the bosses if you want, but it ruins the immersion into the game. You just need to use the Chemist's last move to deal 10k+ damage, which is enough to one-shot most bosses, including the Final Boss. (A guide on how to do is on my other guide). Ps. There is a reference to the Final Boss at the Comic show, when, before you do the Phoenix Wright Mini-game, there is a figurine of the Final Boss.
If all of the bosses are beat... Ps. Doesn't have to be done on the same save file I believe.
Achievement 22 done.

Achievement 23: I Love You Waifu.
When you beat the old man, Waifu turns out to be evil… Bent to destroy the Earth for no reason. Old man gives you a solution, a time machine, you get sent back, you have to choose to either save her from the light bulb or not.
You have to choose to save her, even knowing she’ll destroy the Earth again, in the end. This all in the name of love (I loved this ending one of my favourites).
Achievement 23 done.

Achievement 24: I Love You Gohard (Yes, I do).
You have to be on the Gohard (<3) route.
You have to win all of the fights against the alians. Ps. Read my Boxing King Achievement 15 for a guide on how to beat all 4 alians.
After beating the Octopus, you get a short cut-scene of You and Gohard, fighting.
Achievement 24 done.

Achievement 25: I Love You (´･ω･`).
You need to beat the final boss, then you get the cartridge to go back to the arcade.
You need the Fire extinguisher ($9999).
You need the Revive Barrel too. Ps. You get this from killing Bai WuChang and Hei WuChang.
(Check Achievement 22 to find out how to fight them).
Achievement 25 done.

Achievement 26: All Endings.
Finish the game with all possible endings.
Achievement 26 done.

To be more specific, the final, easily achievable ending unlocks the achievement.

Do it in this order:


A False Step Leads to Eternal Regret:
Attempt to climb into your balcony instead of shooting the lock

Evil Can't Triumphs Over Good:
Tell the Master that you want to bully people with Kung Fu.

Jurassic Journey:
Fail to repair the time device.

A Novice:
Don't click Dodge during Jiahe's first attack.

A Novice II:
Don't click Dodge during Jiahe's second or third attack.

A Novice III:
Don't click concentrate during the no pants Haduken from Wanggang.

No Knowledge,No Win:
Fail to recognise/dodge any kanji attack from "???" the masked girl (name revealed after winning).

She and I in This World: (This unlocks the achievement)
Good end, no special requirements other than not failing.(The Kung Fu training can be failed multiple times and the card game).

Thanks for reading my first guide. This is all of the Achievements. Sorry for getting lazy near the end... If you need help doing anything, please ask, thanks. This was SoraK0917, bye for now. :)

Thanks for bringing this to my attention as I had no idea. And as to whoever made this website, thank you for doing so, it would have been nice to have been notified of this, in some way. However, I am still very grateful. :) (Link is below). P.s. I did not make this website and take no credit or hold any responsibility for the website, but the content, which is the guide, is very well mine.

Link: https://www.guideoui.com/otakus-adventure-walkthroughs-and-achievements-guide/

Also, I have realised my profile is on private so no one can actually add me to DM me. So, I'll make it public for those who would like extra help or just chat about the game or other.

Thanks again to all who checked out my guide.

P.s. If anyone has suggestions for thing I should tweak or change, please comment or DM me, I will probably have a faster reply if you DM me @SoraK0917

Thanks to these people for contributions to my guide:

@SC

@I Have NBN Now

@SUPER-TANK

@LongJohn

P.s If you do not want your usernames here, comment or DM me I will remove it. If you want your usernames up here, just contribute something, like anything, I will add your usernames.