From the Store description:
iO is a physics platformer about size, speed and momentum unlike anything you’ve ever seen before! Grow, shrink, roll, leap and climb in this unique puzzler featuring over 225 challenging mazes and one-of-a-kind gameplay that includes portals, inverted gravity, vehicles and more!
- Play with size, weight and mass to reach the exit as fast as possible.
- Over 225 challenging puzzles to solve
- Intuitive touch controls.
- Unlock Xbox Live achievements.
- Unique and wide variety of gameplay mechanics including gravity manipulation, portals, vehicles and more.
- Retro-futuristic visuals.
The promo video is all we have to go by, so here it is:
You can buy iO the Game in the Store for just under £4 here.