Like, I just remember playing OG Street Fighter II and Mortal Kombat. By comparison, Super Smash Bros is incredibly complicated. But also so fun! I've been learning little by little.
You can change many of the settings in tons of different ways. Normally, the higher the percentage, the more damage you've taken. Big guys can usually take more damage than little guys. It's difficult to know when someone will be eliminated, though. You can get a huge hit on someone with 187% damage and be like, "surely, that got 'em," and then nope.