[Lvl 4+]Sega Mega Drive !

I had a game I don't remember was in 8 bit system (nes) or 16 bit (sega) , there was a hero ( human like ) blasting thru tones of enemies and defeating different bosses and takin their abilities , like u cant breath in water till u kill the underwater boss and take his ability to breath like a fish
its been ages since I played it and since that time I cudnt find this game becoz I don't remember the name