In terms of enemies, I wanted to try something quite interesting for this level. I was thinking of having the enemies be either "Round Captains" or "Round Troops". The troops follow the orders of the captains, who can order them to charge Blocky Man on sight.
Basically, unless the Captain sees Blocky Man, the Captain and the troops will just walk around and patrol. Once the Captain spots Blocky Man, he will order the troops to attack, and they will all chase after Blocky Man. Now here is the catch: if the player kills the captain, all of the troops will freak out and start running around aimlessly in fear. That's not to say that the troops can't hurt Blocky Man when they're are in panic, but they can't chase him in an organized way either.
Now when I say that they will chase Blocky Man, you won't just be able to ditch them by just jumping over a wall. They'll be able to scale relativly high walls in the level, and they brandish spears that reach out pretty far. The only way to stop the chase once it has begun is to either kill every troop(which won't be easy), or to kill the captain and break up the troops.
I like to try interesting enemy ideas in each level, and this sounds to me like it will be pretty fun if I can succesfully implement it.