Okay, so the achievements for this game are quite scuffed. For the "finish the game in XXXX seconds" achievements, you just have to play the game for that amount of time, so you can just AFK for that amount of time to get the achievements, which is what I did.

However, the fall achievements would not unlock, and eventually, it became an eyesore after waiting for a potential update from the developer. Thus, I took it upon myself to debug this so I could get those dang things unlocked. Well, I am pleased to bring you the culprit:

Broken line of code:
GameController.GC.FallsCounter=1;

• This was the original line of code. This means that it... assigns the number of times fell to one everytime you fall. Not based and not epic.

Fixed line of code:
GameController.GC.FallsCounter++;

• This is the corrected lined of code, meaning it'll add one fall each time to your counter, not continually override the value to one. So now, all you have to do is get to a checkpoint (as far as I can tell) and then just run off the edge 50 times and it should unlock. I just wanted this thing uninstalled ASAP so I put minimal effort into this, but it is the fix.

1. You can download the fixed Assembly-CSharp.dll from my google drive: https://drive.google.com/file/d/1BNQy8MaReD1zAp8hBXovDdUE4AbEU9wh/view?usp=sharing
   
2. Replace the my dll with the original at this location: Steam\steamapps\common\HENTAI CLIMBER\HENTAI CLIMBER_Data\Managed\Assembly-CSharp.dll
   
3. Get to a checkpoint and run off the edge the number of times needed to get the achievement (i.e. 10, 25, 50)

Let me know if that works for you. If you are curious about how I figured this out, I downloaded dnSpy (https://github.com/dnSpy/dnSpy/releases) and opened the game and just searched for various combinations of "fall" and "counter" until I found the stuff that indicated that achievements were being unlocked, then I just backtracked from there.