A game where you master lava, electricity and even time.

When I first saw this game, I went "is this Portal?" This game looks and feels like that game, except that you don’t have one-sided conversations with murderous yet snarky AI or murderous yet stupid AI.  

The world is large and beautiful yet abandoned. You wake up from a deep sleep in the middle of everything, trapped within. Again, there are no murderous AIs giving you questionable advice. No gun to open portals anywhere. Nothing but a good grasp of physics. 

In Entropy, a whole world of puzzles are set in your way. All obstacles work within the realm of physics. But, you do have one thing: the creature that woke you up in this place. It seems to know the way out. As you follow it, you acquire the power to control the elements.
These elements are controllable in unusual ways. If Portal was a brain teaser on where holes should go, Entropy is a brain teaser on how things are used, combined (yes you can combine elements) and moved around. Not just moved, but used based on their elemental properties and gravity.

Entropy PC/XBLIG Trailer

And whenever something goes wrong – and it will – you can rewind time back to where you can try a different tack at things. This is great because I’m pretty sure you get one life and one life only. Entropy is a 25-level game full of puzzles that will keep you hooked. No talking AI though. In this game’s case, it’s forgivable. 
Entropy can be purchased from XBLiG for 80 Microsoft Points.