For creative people I can't recommend Backbone enough! It's the most intuitive game making software ever made. You will be able to produce your own platform and overhead run & gun games with ease.
You can use DPaint pictures and animations and mod music for your productions and they're totally interactive. I took a screenshot with as many of the program options windows open at once, just to show how versatile the program is, typically you'd only use one or two at a time so don't let the screenshot put you off if it looks a little complicated, because it's really not. I also have the download links to the three files you need to install it here:
http://www.amiga.org/gallery/index.php?n=3531
