This is about as far as I got with it, mainly due to having such a sketchy spec that I didn't really know what to do next and partly down to the fact that I was starting to work with Actionscript 3 and was more interested in this.
Would really like to start this project up again, maybe one day!
Graphics taken from the old arcade game Midnight Resistance (thanks to Mame!)
Left/Right Arrow keys to move.
Arrow up to jump.
Mouse to aim and fire.