[4/5/16] I converted (mostly) everything from my prototype into something that will be a little more robust. Some engine limitations have led me to trimming a few features off lest their inclusion becomes too much of a time sink.
We now have some level layout, some redshirts to gib, and the movement/aiming controls are finally starting to feel decent to play with.
Posted a (crappy) animated gif showing the new, less-placeholderish, art.
Next, the crunch to give those little red guys some AI and have them shoot back at you, as well as incorporate some HUD elements such as score/ammo count/whatever else comes up.