Not much to say about this level other than these sections being harsh, and there was a lot of enemies all over the place. The backtracking part was interesting enough however there are so many obstacles remaining on the way back that it seems like the amount of time given is too little.
Also I think it would have been a lot easier if you just used lua instead of creating 80 events for the end sequence. The smoke also should have been hidden to polish the counter a bit.