Fourth wall-breaking first-person puzzler Glitchspace is now on Steam Early Access for PC, Mac and Linux, where it's going for Ł4.99 / $6.99.
Developed by the five-person team at Space Budgie, Glitchspace gives players a node-based programming system called Null that allows players to alter the properties of object in the environment. For example, you can turn walls into illusionary barriers and walk right through them, duplicate objects to create platforms, create "switches" so moving one object affects something else in the environment. You can even change the physical properties of parts of the level and apply force to objects. Think Scribblenauts only with 3D map manipulation rather than text-based manifestations.
This might make it sound too easy, but there will be some restrictions to what you can do. Certain objects aren't programmable without the use of an encrypter, and decrypted objects will have default programs applied to them, so you'll have to work within the constraints of the puzzle designers during the core campaign. But if you just want to muck about without prescribed challenges, there's a Sandbox Mode for that.
Even with other programming-based puzzlers on the horizon Glitchspace still looks unique, bewildering and promising. See how it works in the trailer below.