So far all I've done is draw another level background and tileset. Next I'm going to design the level layout, and then write some new enemies.
I think it looks pretty close so far to my design drawing.
Basically, this level will be about fighting an army, so you'll have to fight infantry, tanks, flying battleships, and stuff like that. This is so far my favorite level, and I haven't even created it yet. I just hope it turns out as cool as I'm thinking it will be.