*Sigh*

[lolpoop89]

This Could Of been caused by:
Mod loader
Turrets mod
Me Trying to make my own mod.( I deleted the files but copied over the Entities.png and the appropriate Entity)
So, CAN YOU FIX IT?

[Camewel]

Redownload Mari0.

[Pyrosaur]

Did you make a level using the turrets mod?

[Sašo]

This isn't the place to look for help if you broke the game yourself (which especially includes modding it).

Post in either Mari0 modding or Löve development forum.

And generally it's nice to at least see the code that you changed or the file in which it crashes.