1. Donkey Kong Country 2: Diddy's Kong Quest (SNES) vs. Super Mario World 2: Yoshi's Island (SNES/GBA)

Well, I wouldn't count either of these as the best sidescroller for the SNES. I might have to think about what game I would count as such, but if I had to name now - not counting remakes - I'd probably name Contra 3. Though Contra 3 and Yoshi's Island are very different games: The first being short but tight and intense, the other being long and sprawling.

Anyway, this might seem to be a tough one for me, as I'd give DKC2 and YI the exact same rating. These two games are very similar, both long games in a Mario-vein (though, ironically, DKC2 feels a little closer to an NES Mario game), both games involve finding secrets, which unlocks later stages. Both games are probably about equally difficult.

I'm giving my vote to Yoshi's Island, though. If the choice is close enough to be considered arbitrary, so be it, but I justify the choice to myself on consideration that some of DKC2's secrets stretch the "fairness" of their challenges (what with walk-through walls - even though they're hinted at - and such)

2. MDK2 (Multiplatform) vs. Super Metroid (SNES)

MDK2

3. Castlevania 3: Dracula's Curse (NES) vs. Contra (NES/Arcade)

Castlevania 3

4. Illusion of Gaia (SNES) vs. Might and Magic (Multiplatform)

Pass

Probably wouldn't mind voting for Might and Magic, though.