Zeno Clash is absolutely worth playing, and you might as well just grab it on Steam right now for $3.75. The XBLA version has a few new weapons and lets you play through the challenge tower (which is present in the PC version, but singleplayer-only) in co-op, but the PC version has better graphics (assuming your PC isn't a pile) and controls.
Countdown to the de facto end of the console generation: 5 exclusives
Most recent: Deadly Premonition: Director's Cut (4/30)
Next up: The Last of Us (6/11)
Later: Puppeteer (9/10), Beyond: Two Souls (10/18), Rain (TBA), Until Dawn (TBA)