For all endings, you must click on the ending icon in the ending tab to unlock the achievement. Otherwise, they will not unlock.

Play through all 30 levels.

Level 14. Use the spray bottle on the persons face until the screen shows full green and fades to black. You can hold down left click.

Level 21. Break the window with the hammer. Once it will not break anymore, drop the hammer with right click and left click on the black hole on the window.

Level 13. Click the door to reveal the man. Close and open it again until the jumpscare. It takes 4 clicks.

Hold the space bar until a noise is made. Then release and repeat. Do this about 14 times and the achievement will unlock.

The Flood - Forget about water

Turn on the water on the left side of the screen and leave it on till the end of the level.

Level 4. Click on the bird in the tree in the window.
https://steamuserimages-a.akamaihd.net/ugc/2285079210231717414/98A9DC690516825A5FE9227D2574C3F20BF653A1/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Level 7. Click on the fly to kill it.

Level 10. Click on the key, then the door. Click the chest that is now shown in the doorway. Open the cabinet and click on the chest 2 more times. A flower will show up on your screen when you have done it correctly.
https://steamuserimages-a.akamaihd.net/ugc/2285079210231717765/3E6ED0BCE6514EA8653DB2D8A5218F104287C400/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
https://steamuserimages-a.akamaihd.net/ugc/2285079210231718005/EAB06C07266C22DF59AC221A8E180CC4B400E494/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
https://steamuserimages-a.akamaihd.net/ugc/2285079210231718412/6C11F3074A666191AE478D26908F8775322562CF/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
https://steamuserimages-a.akamaihd.net/ugc/2285079210231718882/CEC69EDB093E852889A8C2B9EAB3036235208BD7/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
https://steamuserimages-a.akamaihd.net/ugc/2285079210231719245/907C97513EE01EA621D516A5F0F442AE3CBE35B1/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Level 14. Open the cabinet and click on the spray bottle. Spray the bottle on each of the 3 bugs.

Level 21. Open the cabinet and grab the hammer. Click the lamp.

Level 28. Open the cabinet and grab the cloth. Clean all 5 spots.
https://steamuserimages-a.akamaihd.net/ugc/2285079210231719588/CFB0B9B7C92A7B73F9C4CEF45ACE2FC9229E6534/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Left click on the bottles to smash. Level 5 has 3. Level 12 has 1. Level 19 has 1. Level 24 has one.

Right click on the bottles to drink. Level 5 has 3. Level 12 has 1. Level 19 has 1. Level 24 has one.