In all of the Mario games I played (which are not that many), I have to take down Bowser with three hits. I was wondering which Mario game first had that specific gameplay mechanism, since it seems to be used in a lot of games.
Super Mario 64 (1996) is the first game that did this.
Super Mario Bros. (1985) you jumped on an axe. That's out.
Mario Lost Levels (1986) you still jumped on an axe. That's out.
Super Mario Bros. 2 (1988) ....is out.
Super Mario Bros. 3 (1988) he kills himself or you shoot him a lot with fireballs. That's out.
Super Mario Land (1989) you're a ship not even fighting Bowser. That's out.
Super Mario World (1990) you have to hit him with Mechakoopa's 6 times! That's out.
Dr. Mario (1990) is a Tetris-like game. That's out.
Super Mario Land 2 (1992) you fight Wario! That's out.
Mario Paint (1992) doesn't have fighting. That's out.
Super Mario RPG: Legend of the 7 stars (1996) Bowser is on your team. That's out.
Yoshi's Island (1995) is a 2 phase fight where you throw eggs at Bowser at the end 3 times so it wins second prize.
Thanks to Denilson Sá Maia for a couple of games here.