Not Source engine - Source, the third-person Metroidvania in which you're a little electronic butterfly-thing in a huge, gorgeous cyber-world!
"SOURCE is a metroidvania action adventure game for next gen consoles and PC. Existing in an alternate dimension, you control a firefly creature with the unique power to manipulate energy with every living being in a strange, bio luminescent world. However, this world is being devoured by a sinister and relentless dark energy that is literally tearing the world apart, and it is your destiny as the last of your kind to stop the terrible threat of extinction.
Immersed in a stunningly beautifully rendered 3D environment using the latest in high end particles and lighting, you will face many mind bending puzzles, explore vast lands, and combat powerful creatures while constantly seeking new and powerful upgrades to aid you in your quest. You must navigate a deep, lush biosphere ecosystem and learn how all the various and strange creatures and foliage behave, some helpful, some harmful. You will need to discover where this evil SOURCE is coming from in hope of ever restoring balance and peace to all living things."
I've had a heckuva time finding release dates and windows for some of the more interesting indies at this year's E3 - I still can't find anything on how Galak-Z's coming along - so this was very nice to find on the developer's site:
So it's a ways off, yet. Thank you for letting us know.