If I may, a couple games with good + satisfying shot to kill ratio:
Nuclear Throne (you can learn a lot from this one)
Mega Man (any of them really, but I recommend 2,3, and 9)
Gunstar heroes (this game is pure chaos, but still gives a good idea, and it's one of my personal favorites)
Not that you should copy these, but I found these games are all very satisfying when you blow things up.