If you want to be cool and sad like the rest of us:
1. Play the puzzles and finish them.
2. Go on steam and be confused because you can't find a guide.
3. Search and only find answers not in English that don't initially work.
4. Have boyfriend search.
Boyfriend knows computer things.
5. Have him change settings; see guide below.

Congrats! You now have all achievements!

Go to your Program Files (x86)\Steam\steamapps\common\Happy Anime Puzzle\Config
Open Settings in Notepad.
Change the false to true.
Change levelsStar values to 50.
Change LevelsTime values to 60.
Save.
Open the game.
Open all of the puzzles one after another. Just keep opening them. Over and over until the achievements pop up.