all I know is that I find wall jumping really really hard to pull off. I've managed 4 in a row and I've managed once or twice to get to areas that I sohuldn't have been able to by jumping just vertically... but I know I find it hard to pull off reliably. Every other game that has wall jumping is much much easier to do.
The quicksand can piss off though. Thankfully by the sounds of it, it's just a couple of rooms and I'm not far from getting something that helps with it.
Cracking game though. I'd probably still put Zero Mission above it so far but remember, I never played Super Metroid on release, never had a SNES and didn't actually properly play Super Metroid until it appeared on the Wii VC.