From Gryzor (Contra) to Atomic Runner to Gunstar Heroes, Run 'n' Gun games were a staple of retro gaming in the 80's and 90's. Here's my top 5 spread across a number of formats.
5: Contra (aka Gryzor aka Probotector) - Arc/Spec/Nes/Snes/MD/C64/CPC
Take Predator, add more aliens that look like they're rejects from Aliens, add another selectable character with loads of different power ups, and you have Contra. Why they renamed the game to Gryzor and Probotector for us I'll never know. Mind you, Gryzor is a pretty good name.....
4: Gunstar Heroes - Sega Mega Drive
Developed by Treasure, GH starts off as your normal run 'n' gunner, until you get to the final level, and a massive board game which determines who you face. Mad? yes. A novel idea? absolutely. Does it work? in leaps and bounds. And who doesn't want to face off against a boss called Curry & Rice?
3: Aliens - Arcade
To date, I think, only the second of Konami's licensed cabs alongside Asterix, Aliens takes liberties with its source material, like introducing a host of other alien types (flying alien, anyone?). Still, it does make for an excellent game (more info in an earlier blog post).
2: Ikari Warriors - Arc/Spec/A500/ST/C64
A top-down shooter scrolling top to bottom, Ikari Warriors saw you, as a character that looks a lot like Rambo, take on an endless amount of bad guys, by gunning them down or throwing a limited supply of grenades at buildings or gun emplacements. Plus, it's great to play and look at.
1: Rambo III - Sega Mega Drive
This version by Sega, has a suedo top-down perspective, and sees you running and...erm...gunning lots of Russian troops, freeing prisoners and placing bombs at gun walls. Plus, you can use explosive arrows to blow up trucks. Looks great, plays great, sounds awesome.