You can consider Ultratron as topdown shooter, just change your way to view it and sprites.
So, I took your advice and now you can press multiple keys at once.
http://www.mediafire.com/?6pde8xt7e8xl7h3
If you’re interested.
It works
I’m glad.
I don’t know if it’s just me, but it seems to move a lot smoother now… XD