One of many 7-Day Roguelikes created for this year's challenge (which Mr Smith will be presenting a more fulsome guide to in the not-too-distant), free browser-based game-ette Me Against The Mutants further complicates the risk of perma-death with the concept of 'Infinities.' Either you're trapped in a repeating angular vortex or you need to create one of your own in order to get the drop on dangerous enemies. Drag a square and anything it will be replicated to fill the screen - including you.
One moment you control one Rogue, the next you're controlling dozens, moving in perfect synchronicity but, once you've passed through the psychological barrier of 'oh God what the hell's going on I can't control infinite men my brain hurts aaaargh' offers fiendish ways to gang up on powerful foes. Infinities also enable you to access otherwise closed-off areas, by temporarily replacing solid walls with replicas of what's beyond them.
Oh man, I've made a right pig's ear of describing this. Someone else have a go. Or just play the thing, it's proper clever.
Via Freeindiegam.es, a worthy new project from Terry Cavanagh which I'm a little jealous of. If only we could use Infinities to clone RPS' staff, then we could be doing similar here.