If so ther'es a version of Xenon 2000 you can download 12Mb and misses the classic dance track but pretty good, http://www.bitmap-brothers.co.uk/features/xenon2000/index.htm
Top to bottom with a little side to side. It was one of the first games t have parallax scrolling, had a huge array of upgrade weapons and a sountrack written specially for it my Bomb the Bass. [yt]Fv8n1HUyJbo[/yt]