Don't waste ammo, don't stop moving, and whatever you do, don't turn on the lights.
We haven't seen much lately from the "Metroidvania" school of game design - side-scrollers built around finding new gear that not only enhances your combat capabilities, but also lets you access new routes of exploration and progress that were previously unreachable. It's an old-school concept but Netherlands-based developer InterWave (creators of the oft-overlooked multiplayer gem Nuclear Dawn) is bringing it back with Dark Matter, which the studio describes as "a modern descendant of Metroid." Featuring an emphasis on challenge and tactics, Dark Matter tasks you with surviving an infestation of alien creatures that do not appreciate getting blinded by your flashlight.
The plot might not be terribly original, but Dark Matter spices things up with its dynamic light-based AI. Aliens are enraged by exposure to light and will come charging if you aren't careful with your flashlight, but sneaking around in darkness leaves you vulnerable to unseen attackers. Combat is unforgiving enough that you'll want to engage the enemies on your own terms, so you'll have to learn to balance light and darkness if you want to survive. Along the way you'll pick up a collection of upgradable weapons and equipment.
InterWave is taking Dark Matter to Kickstarter to secure funds for the final two months of development. At the same time, a Steam Greenlight campaign is in progress for the PC release, though InterWave is offering the game as a DRM-free download as well.