What does this error mean?
Whenever the laser hits an enemy (use space to launch), the whole program breaks with a weird error. Can someone help me figure out what the error means?
System.InvalidOperationException: Collection was modified; enumeration operation may not execute.
This likely means you added or removed an item of a list you were iterating over with a foreach loop. I think it's the one at line 98 where you call
enemies.RemoveAt() in the foreach loop. This is illegal, so just replace it with a standard for loop.