Kerbal Space Program | Steam | £11.99 (RRP: £19.99)
Kerbal Space Program is still in perpetual Early Access, but quickly established itself one of the most unique and challenging games on the service - and a game that's worth buying into. You're tasked with building rockets in a brutally realistic simulator, watching a thousand embarrassing crashes before finally creating something that can break the atmosphere. Which is where the real fun begins. Part edutainment, part puzzler, part simulator and all awesome, this will keep you going for a while - and you can save the best part of a tenner until April 8th.
Thanks to GobbleTurkey @ HUKD!