Uh... put more distance (depth) between the floors, maybe make it a little more interesting by adding some more stuff in, make it a little bigger... that place is going to be an absolute slaughter house. You'd spawn and get killed within, like, a second.
Not bad for a start, but you need to make it more interesting. Add more to the map than just two floors, add lots of detail to the map, and while working on it some more, think what makes your favorite maps so good and use that as a springboard to more ideas.