Soulless is a side-scroller action game that was developed by Cobra Blade and released in 2008 for Mac. The original concept of the project was a quick Wizard of Wor style game with Space Marines against zombies, but it later became the side-scroller action game that we can play today. In the beta version the space marine armour was different from the final one.
Thanks to Cobra for the contribution!
Beta (click for bigger version):
Final (click for bigger version):