ok the problem is in the event :
System EnemiesRemaining = 0,
Go sprite Is Ready System
set EnemiesRemaining to WaveNo * 3.
I will explain what is wrong with this; In the event that "spawns" your enemies you are doing this:
System Every 1.0 seconds
System EnemiesRemaining =0
System set EnemiesRemaining (EnemiesRemaining-1)
so when this condition gets to 0 the event mentioned before sets the variable to WaveNo*3 so it will never becomes 0. You will have to find other way to update your EnemiesRemaining for each level. Hope it helps
Edit: I didnt realize and you toggled some events off but not quite correctly, delete or toggle the DEBUG events correctly or you will keep the strange infinite create object behaviour you are having right now.