The game itself, after playing it so many times and getting it down to where I got it on v.hard, is relatively easy overall. But there are a few sections that are still totally hit & miss for me on impossible:
Kirby Area:
-the initial jump over the spike wall thing, sometimes I just jump a hair too short because I try to avoid falling off the edge before I jump.
-the first jump when you enter the cave, that double jump over those two spikes is so 50/50 for me still at this point that it's infuriating. If I make the jump over the spikes, the fall and subsequent jump over the next spike to avoid the falling ceiling is cake, but knowing where to start the first jump, and when to trigger the double jump, is absolute pinpoint accuracy that I haven't gotten used to yet.
That falling ceiling room after the clowncopter trio - I double jump into that lower-hanging spike way too much for a person with <5 deaths on v.hard.
The couches - all rooms considered, sometimes I just jump too high or too short.
Megaman area:
-quickman beams - there are two parts to this room that are totally chance for me. Making that first jump down and making that tricky double jump so that you avoid the first beam is serious business. Also, the final stretch of blocks that float both up and down...I'll replicate the same way of doing it (hitting the first block that moves up and then walking across so I keep landing on the next one, being brought up, and falling on the next one) and sometimes the kid'll do it with no problems, or he'll fall through a cube. This is just glitchy movement, but it's frustrating.
Mine cart ride from hell - pretty much every jump that requires a yellow slingshot, they're all placed so maliciously. Screw the last stretch with those slings through the small openings, so freaking evil.........<3 Kayin.
Tower of The Guy - That room before the labyrinth, you have to make sure that you start your jump down to the yellow wall at the proper time, otherwise you're fucked and when you do make the jump over to the platform, you'll miss. I eventually did figure out when to start my way to that wall, but it required so much trial and error.
Hall of former guys - Lu Bu room - gotta love those apples (I noticed that the apple placement is significantly different in RC2, seemed easier, care to elaborate, Kayin?)
The Guy - ......what else can I say.
Everything else in the game can be done with relative ease now (yes, I'm including all of the ghosts n' goblins section in that statement).
Things that were stupid hard but are now super easy:
ghosts n' goblins
that warhead jump after mecha birdo
dracula
mother brain
that weird double jump required to make it past link without him spearing you to death. (the second one, not the one over the spikes)
There's more, but...i'm in class.