When you die all of your progress before you saved is reset. Save frequently. (Or enable auto save, but I would still save after you collect amber or wildling wheels. Your damage to enemies is also saved, so if for instance a certain spider boss is giving you trouble, you can heal but he can not :)
Another thing to note is that I closed the game after getting each ending just in case my save got wiped and I had to start a new game. This might not be necessary, but I find it worth mentioning.
One more thing! I completed all of the achievements with the balanced class, but the explorer class makes climbing sections much quicker. Have fun!

Secret room
Find the secret cave in front of the start of the game
At the start of the game, destroy this mushroom and enter the hole.










Complete the game
Build level 5 village
Resources can be found in buildings, dropped by enemies, and by breaking mushrooms of all kinds across the map.
Level 1: 5 clay, 5 mushroom glue, 2 iron, 10 wildling wheels
Level 2: 10 iron, 10 bronze, 10 limestone, 20 wildling wheels
Level 3: 20 limestone, 20 clay, 25 mushroom glue, 30 wildling wheels
Level 4:5 flower pollen, 15 clay, 15 iron, 50 wildling wheels
Level 5: 3 amber, 25 limestone, 25 bronze, 100 wildling wheels
All 5 levels: 40 clay, 30 mushroom glue, 27 iron, 35 bronze, 55 limestone, 5 flower pollen, 3 amber, 210 wildling wheels

First Progress
Build level 1 village

Randy and Bibus
Talk to Randy and Bibus










It’s not a lie
Your character is really called Ray when you talk to Randy and Bibus











Yellow Billy
Talk to Yellow Billy










Goal!
Pass the ball through a statue at the entrance to the city
The ball is located just left of the route to Yellow Billy. Hit it down and toward the statue. The achievement will unlock before you actually get the ball through the "goal".














The Yellow Door
Open the Yellow Door
Continue pushing the ball forward and to the left of the statue until you reach the yellow door. Inside are 100 wildling wheels.











Collect 100 wheels
100 wheels in your Wheels Container


Aagor
Talk to Aagor
Notice the light in the building. Aagor's up there. There's also one amber for your troubles.











Collect an Amber
Collect an Amber


Barny
Talk to Barny
Barny is located on the other side of the ravine toward the ocean.











The Highest Tower
Climb to The Highest Tower
Past The Dark Shaman, there is a climbing section after which you will reach the highest tower. There are 50 wildling wheels and one amber located here.











The Arm Museum
Find The Museum of the invention of the arm
Just below the highest tower is the museum in question.










Mylo
Talk to Mylo










The real world
Discover the real world
This requires finding Ann and following her through a portal.










Destroy the Dark Shaman
Find a way to get rid of the Dark Shaman
Destroy the doll.










The Land Bellow
Find The Land Bellow
Take a left instead of continuing forward toward Ann.










Waterfall Cliche
Find the secret behind the waterfall










Bad Ending
Get to level 5 of enhancement by the Dark Shaman
This requires a total of 420 wildling wheels to complete. After you have reached level 4 you're tasked with killing Mother for her wheels. After doing so return to The Dark Shaman to level up one final time.










Find Mr Llun
Hidden achievement: Find the biggest secret in this game
Proceed to the end of the bridge and jump or walk off the end. It may take you a couple minutes :)










Kill A Spider Boss
Kill A Spider Boss
There are spiders located in three different places across the map.
The cave right of your starting location, across the bridge, and in the land bellow