In the game, you make a decision every end of the storyline.
You won't get all Achievement in one playthrough. So you have to make at least two runs.
One Achievement can be only done, if you take particular storyline's in a particular order. And don't forget to take one of the Items from there. It is essential in the next storyline.

I made this Guide, after I run the game two times. So if there is misinformation, just comment it.
Also, I'm not an English is my second Language, so there may be some mistakes.

In the early stage of the game, there are only missable Achievements.

A Dirty Job - Clean all the dog poop.
This one is easy to get. Left from the INN is a Poop Bag Dispenser. Interact with it and collect every poop. After you took the last one, don't forget to go left then down to talk with the Lady, she is going to give you 10 Bucks. And empty the Bag in the Dispenser.

Pickpocket - Commit two acts of theft.
This one is mean, for this you can only interact once with the wardrobes, after that you don't get the option for theft.
In the INN, there are on the bottom floor two rooms. Go to the left one (Where the man is sleeping) and interact with the wardrobe. Take the Money from his jacket.
The second Item is on the upper floor. There is a wardrobe in the left room, interact with it and take the watch.

Coco Nut! - Knock down and eat a coconut.
In Greyfox walk down to the harbour. Besides the Hospital are two Palms. Go to one of them and interact with it many times. Haven't counted how many times but after a while a Coconut will fall of. Pick it up and eat it through the Itemmenu.

10. Tea Bagged - Have tea bags dumped on you.
Walk as Mable in the House with the teapot over the door (Cafe?). Then go to the upper room. There is a cutscene and you will get the Achievement.

Mabel - Complete Mabels's storyline.
I don't have to add anything.

The Nurse - Complete the nurse's storyline.
The only Achievement in this Route.

Mr. Brown - Complete Mr. Brown's storyline.
No comment.

Not an Achievement, but will help you later: On the upper left room is a Lady in a Wheelchair. Go to the Bookcase and interact with it. You will get a Dog Cookie. It will help you in Katharine's storyline.

Here Kittey~ - Save all of Katharine's cats.
Go to the groceries and buy the Carrier. Go back to your home and put every of your 10 cats in the Carrier. Don't forget the basement. Go to the habor and give the now full Carrier to the sailor.

Scam Artist - Have Esmeralda arrested.
Go to the upper part of Greyfox and give the dog the cookie. Walk the passage and talk with the Lady over the hole. Say that Esmeralda is in the city.

The Kat Lady - Complete Katharine's storyline.
Just finish it.

Cake! - Finish the game.
Just finish it. Your decisions don't determine if you get this Achievement or not.

Happy Ending - Get the good ending.
Don't Pickpock and let everybody live.

Saved - Don't kill anybody.
Well, it does say it.

The Doctor - Get the so-so ending.
Kill at least one and let at least one alive.

Heartless - Kill everyone.
The evil one.

The Asylum - Get the bad ending.
Steal everything and kill everybody.