Unmarked spoilers are ahead, per Spoilers Off rule.
Ristar defeating Kaiser Greedy in the final boss fight. It can be summed up as: Cute Star with stretchy arms vs. Alien Emperor that can summon mooks, projectiles, lightning bolts, and black holes. Cute Star: 1, Alien Emperor: 0
The ending, with Ristar escaping from Greedy's base as it explodes, followed by a Bond One-Liner that's a Shout-Out to Terminator 2 of all things. Then the end credits that not only feature Ristar interacting with characters from each level, but also feature a border of Ristar sprites animated perfectly in time to the Awesome Music.
