It's pretty much my fave game (T1 and 2) - I'll give it a ruddy good going on over when I'm back on XP. It's good to see Turrican getting some loving in a Mario/Zelda/Metroid/Sonic obsessed world.
I think the slide distance needs reducing.
He seems quite heavy too when falling. It feels just like he's under a waterfall from Turrican 2 but with a higher jump reach.
Waterfalls don't push down?
The hang time and jump are bang on though.
Plus I don't know how but I managed to make him fire the flamethrower and still walk around too.
You can crouch in mid-air.
I really like the level design though. It's all very Turricanish. I also don't know if these changes are in the C64 version, I only played Turrican on the Amiga.