Try it. It's fun.

Basically it's a low res pixel based platformer that uses randomly spawning levels and area level feelings (IE messafes indicating a special room feature) ala a roguelike. I found the controls a tad awkward, but overall a very fun game, especially considering it was made with Game Maker.
I've tried Spelunky. I agree th controls were awkward, though I also couldn't get into it as much because of the time pressure--it's a little too willing to throw that stupid ghost at you. I love the idea of a Roguelike platformer, but it's a little klunky in a lot of ways.
I too disliked the controls. It's the type of game where you're going to die a ton before you get anything effectively done. But once you get the hang of it, it's rather fun.
Aside from the graphical improvements in the XBLA version, it doesn't look like it'd be hard to create a similar game with BYOND. If you don't like the controls, make a game like it with better controls =)