Collect one of the weapon supplies. The first one you can find in the tutorial level, it is inside the box with a question mark drawn on it.
Please stop the music!
On each level there is a gramophone playing a music. Just pick it up and throw it against a wall with a full force.
Just complete the first level.
What is going on
Just get yourself killed, the easiest way to do it is to jump into the toxic water in the level 3.
Pick up healing power-up, you can find some in level 4, 6 and many others.
Enter the secret room in level 9 and use the buttons on the desk, one of them opens hidden trap in the floor, when cardboard man will fall down into the water you will get an achievement.
All you have to do is using holy hand granade, you can find it on example in level 24 on the top of the construction or you can try to spawn it in the sandbox level after completing the game.
Lost and found
Complete level 12
Just fooling around
Enter Sandbox level from the main menu and walk around the location.
Flat Earth Society
Complete level 25
Third arm has grown
Complete level 27
You can find a pyramid in level 17. You have to go to the top of it. It is not enough to enter the small room on the top of the pyramid, you have to go on the top of that room.
The Spiral of Madness
You have to complete the game and go through the final level.
In the final level, when Cartonface asks you to go left, do not do that. Approach the cabinet and pick up the medicine by pressing “E”. The door on the right will open, go through the corridor and leave the warehouse.
The hidden art gallery is in the level 14. To get there, you have to climb on the shelf on the right. Then jump onto metal beam, and then you have to do some jumping on metal beams attached to the wall and the dispenser. At the top of the warehouse there is a gap between roof and the wall, wide enough to walk through it.
There are two levels in which you can beat that record – one is level 16 the other one is level 2. There is not much to say, it is all about trial and error, you have to start sprinting since the beginning of the level and focus solely on getting to the key as fast as you can, then throw it to towards the exit, try to do it during walk, and then sprint back to the exit. After few times you should find an optimal way to run.
Random, random, random
In level 35, go to the right side of level and to the back of the castle, you will find a slot machine in there. Press “E” button to start the machine. You have to get three identical symbols on it. The results are randomized so probably you will need some patience to win the prize. The prize is a random weapon supply.
You have to get to the top of the tower made of boxes in level 37. The easiest way to do it is to get to ground floor of the tower (by pressing buttons and avoiding attacks). Inside the tower there are a few teleport supplies. Collect them, throw one of them on the top of the tower (be aware to do not destroy the tower) and the next one nearby you, then teleport yourself on the top of the tower. Do some walking there and you should get an achievement.