I found an error
Error
powerup.lua:16: attempt to index local 'world' (a nil value)
Traceback
[love "callbacks.lua"]:228: in function 'handler'
powerup.lua:16: in function 'createPowerupPickup'
game.lua:45: in function 'fn'
libraries/tick.lua:105: in function 'update'
game.lua:108: in function 'update'
main.lua:55: in function 'update'
[love "callbacks.lua"]:162: in function <[love "callbacks.lua"]:144>
[C]: in function 'xpcall'
It may be useful.
Anyways very good game :)