Yes, initially i didn't notice the map generation, but that's admirable. So i guess you can't really setup the level to avoid collisions.
Then probably a path finding algorithm would be the approach i'd use. It's a bit more advanced, but try checking out this video.
Also, good job on the sound effects, only maybe they are a bit too loud. You can easily adjust the volume, both from the editor and from code.
I guess the only thing missing is for the enemies to shoot at you. And about that, you can shoot through some obstacles, you they are thin enough ;)
Good work