Drop box worked well (for anyone else just download as zip-- topright corner.)
What I see:
At ~31 seconds the mass spawning happens and a 'beware ogre' watermark spawns ( db.tt/vo2DriMG )
I reckon it's between lines 22 and 23.. have a fiddle.. I'm going to!
Edit: Scratch that.. has to be between 4 and 12 as it is just 'Enemy' which mass spawns not Enemny 2 (lines 22 and 23)
It is related to line 8.. no idea how. Try disabling line 8 and the mass spawning is instant.. so that line (8) is disabling something.