The first map was a disappointing one, because the layout of enemies were ok, hiding in the shadows, but since you can lure one at a time it became boring and obvius. BUT, it could be like, one enemies to show de concept of the map and when you get the super shotgun, all enemies becomes active (or all enemies from the side you picked first)

The second map was the hardest, since few maps used the enemy jumping mechanics (I think I saw once in an honey map, but the enemies were always far away, vores and such). The shambler was strange and fun, but once you realize you can walk on the plataforms and no need to jump, its a cake walk.

The name of the third one describes it well. Maybe put some enemies to go back on the gold key door?