After completing all the available achievements in the game i tought ' i did the achievements, what can i do next in the game ' , then i came up with some interesting ideas:

• bunnyhop from start to end
  
• kill all enemies from start to end
  
• try to open as much containers as possible
  
• make the most OP weapon as possible
  
• survive all the levels with only 1 heart
  
• find the secret rooms

Realy these were just my ideas, and i did all of them, you can think of many more possibilities that you could do.

If you found this interesting, you could trade some stuff with me;)