I've invested a lot of time in Super Street Fighter 2, Ultimate Mortal Kombat 3 and Castlevania 2 for really old games. Super Mario 64 deserves mention too.
if u liked that then u might like Evil invasion, was a bit similar, otherwise u must have played Alien shooters games right? kinda the origins of it all
on of the old school gem for me is I of the Dragon its a real time RPG u play as a dragon, its buggy and a bit rare but still fun to play. otherwise Jets n guns is a must know and play as well of course.
check out babo violent or teeworlds as well there r super simple but lots of fun