Original: Indie developers Wolfire Games and Unknown Worlds have joined forces to offer 40% off pre-orders of their respective games Overgrowth and the Natural Selection 2 Special Edition in a $40 Organic Indie Pre-order Pack.

In addition to copies of the games upon release, pre-ordering brings early access to both. Overgrowth playable alpha builds complete with editors are released weekly while NS2 has delivered its editor to pre-orderers and will also bring alphas, as a trailer explains.

Overgrowth keys will be able to activate the game on Steam and Impulse. Unknown Worlds hopes Steam will support activation of NS2 keys but it has yet to be confirmed. "We do expect it, but it's out of our control still," founder Charlie Cleveland told us.

Natural Selection 2 is a sci-fi RPG-RTS hybrid and sequel to the excellent Half-Life mod, while Overgrowth is an action platformer with "brutal physics-based ninja rabbit combat."

Cleveland explained in a recent interview with Shacknews that pre-orders were hugely important to NS2's development as "the only funding we're currently receiving."

Overgrowth will hit Windows, Mac and Linux at a time yet unknown. Natural Selection 2 is expected early this year in a Windows flavour.

The Organic Indie Pre-order Pack can be bought for $39.95 direct from the developers until 10am PST on January 11. As a bonus, those who have already pre-ordered one of the games can pick up Overgrowth or Natural Selection 2 for free, as appropriate.

We also have five Organic Indie Pre-order Packs to give away. For your chance to win, simply leave a comment we'll pick our winners at random then notify them by Shackmessage tomorrow.