For starters, the fact that this game, this FLASH game mind you, was a labor of love that languished in Development Hell for years. And eventually, it has finally been released on the internet, totally for free, to universal acclaim. The best part is that they managed to stay true to the game play of each game they represented, they kept the graphics the same, the animations similar, and it truly is deserving of the title of the ultimate tribute to the NES glory days of gaming.
The end of Pro Wrabobo. After becoming frustrated at the Balloon Fighter stage and spending a good solid several minutes decking The Amazon continuously with punches and suplexes, the moment the Amazon's health reaches zero is when your Rage Meter peaks. Pressing A and S starts the finale of the stage, with Abobo pile-driving the Amazon back into the center of the ring. Then Abobo summons four WWF superstars, the Ultimate Warrior, "Rowdy" Roddy Piper, The Undertaker, and Hulk Hogan. Each of them do their respective moves, until finally Abobo gets his turn, and jumps far up out of the stadium, into space, carrying The Amazon over his shoulder all the while. He eventually comes back into the atmosphere at terminal velocity, crashes through the ceiling, and utterly destroys the entire stadium with the resulting explosion. The Amazon doesn't even die from it. It takes some Megaman Spikes Of Doom to put him out. It's more awesome than can be put into words.
The Contrabobo stage: being able to meet (and of course kill) Rambo, Toxie, Jason and RoboCop in the space of a few minutes.