OVERRIDER - Hoverboard tricking combat, seemingly Open World.

REAL WEB LEGENDS: Carter's Quest - VERY COOL. Comparable to Ocarina of Time/Wind Waker. Nice low-er poly style and drawn face expressions. Neat music. Honestly seemed iffy at a glance, but now looking forward to it personally.

For anyone maybe looking for interesting demos to try during Steam Next Fest:

The Mobius Machine - seems like a neat Metroid type.

Doggy Don't Care - funny little casual dog game.

ARTIFICIAL - first person sci-fi environmental puzzler, sorta like Portal and Half-Life. (iffy comparison from me)