Pro tip: Invincibility in Ring King

Ring King is a kind of tough game. You have to take your underpowered boxer up against a whole host of guys much more powerful and skilled than you are, which hardly seems fair.

So that's why I like to even the playing field a little bit.

When you're at the Training Gym screen

Grab a couple of controllers (or an NES Advantage with the snazzy switch to toggle between Controllers 1 and 2) and (quickly) press the following sequence.

Controller 2: A, Controller 1: A, Select, A, Controller 2: B, Controller 1: Select, Controller 2: A, B, Controller 1: B, B

You won't get any confirmation or anything, but when you go to the match, you'll notice that you can take all the punishment the other guy can dish out

And it won't cost you any stamina

You will actually have to land a few punches if you want to win, though, so it's not a total cakewalk.