Eversion, Windows

Developer: Zaratustra Productions
Year: 2008
1 Player

Sounds - possibly musical - heard in the night from other worlds or realms of being.  - H.P.Lovecraft

Eversion is an indie game, originally available for free on the developer's website, but has recently received an updated version for purchase on Steam.
It is a bit of a retro-chic platform game, borrowing elements from the ever-popular Super Mario series (collecting items out of boxes, enemies you jump-on to defeat, trying to save the princess...), but to call it a cutesy Mario-clone would be a disservice; Similar to Braid (also available on Steam) it's more of a puzzle game, although there's still plenty of platforming in it.

The puzzles in the game have to do with navigating between different layers of reality by 'eversing'. Throughout the levels, you will occasionally come across areas where the background imagery and music changes a little. By pressing the Everse button at such a point, you cross through to a slightly different version of the world - the basic structure is the same, but the appearances and properties of certain things shift a bit, such as clouds becoming solid platforms or being able to walk through the trees. These eversion-points are sometimes marked by, say, a pair of flowers or a couple of gems, but not always. (To make things easier, in the Steam version you can press everse to have the game show you any eversion-points which may be on screen.)

The game is relatively short - only eight levels - but certain bits of it will likely take you a while to work through, and upon completion you unlock a time-trials mode for added playability. Furthermore, a third-party Level-editor has been released, allowing folks to create their own add-on levels for the game. (The commercial release even officially supports the addition of said add-ons to its time-trial mode, and there's an achievement for trying to edit the main game files.)

All in all, I think Eversion is a pretty cool game, and well worth the fiver they're charging on Steam. Just be careful to heed its warning: Not suitable for children or those of a nervous disposition. If you're in the wrong frame of mind, the later levels might freak you out.