Sonic & Knukles.
15. Sonic & Knuckles (last year 16) first impression 9, replay 8.5, technical 9
Pros: This was the epitome of the 2D Sonic formula, in terms of diversity of power-ups, gameplay mechanics, bonus worlds, and multiple ways to play through multiple characters. Knuckles is awesome, Blue Sphere is awesome, the combinations with Sonic 2 and Sonic 3 make for a game of unprecedented scale at the time.
Cons: The game really forces the "Sonic & Tails" mode down your throat as the preferred setup, so you cannot experience the full game unless you play a certain way.
Monster Hunter: pissing me off since 2010.