MagMax (NES)
The thing that I enjoy most about this game is the level of ship customization, there are various robo-body parts that can be picked up throughout each level - each acting as an additional gun for your ship, that can be acquired in pretty much any order. The option of playing above ground or underground is another unique trait of this memorable shooter.
Guerrilla War (NES)
Anyone else a fan of this classic? It's so fast-paced and action packed. I'd take this game over any stinky Black Ops any day. You get unlimited continues, and always start off exactly where you died, so it's as if the developers are insinuating that you play the game as chaotically as possible... which is an absolute blast. Easily one of my all-time favorites on the NES.