The intro sequence and ghost trail are nice touches, and good work getting the dudes to follow the player around the level layout. It's definitely a good concept and I hope you continue! For some nitpicky constructive feedback, I noticed for the most part the enemy spawns were off-screen, but in one area in the upper right of the map they could spawn fairly close to the player. And the enemies could dodge all the walls, but on the one threshold on the lower right they could get stuck if I stood to the left of it. I like the idea of dealing with the enemy swarm and attempting to find a fairly safe place to regain energy, but after a while the spawn rate seemed to be so low that it took a half or full lap to find another enemy. Aside from that, I can imagine pickups and new abilities would make this really enjoyable.
Great work!
-Scott