Part I

First part of the sewers level birds eye.

Enter

       Enemy attacks from the top of the tube the character walks through. Three enemies lay in waiting and attack when character gets within proximity. After a certain number of deaths ( one or two ) another enemy jumps down from the vent.
Three enemies attack from the tunnel with a blockage at the end ( the player can walk down just to peek round the corner, but not past the blockade - this gives the player the idea the area they're in is bigger than it really is)

Second screen

       Player gets half way, sees one enemy climbing down the ladder but to not give the player an advantage, two enemies attack from behind to allow the other enemy to get down the ladder.
If the player doesn't kill the behind two in time, another enemy will come down the ladder ( one enemy per 10 seconds still in combat )
Once all are dead the player can climb the ladder and progress onto the next part of the level.