Bundle Stars Build-A-Free-Bundle

Imaginatively dubbed "Build Your FREE Steam Bundle", Bundle Stars have teamed up with PC Gamer to bring five games, one each week, to you!

Starting off with SpaceChem today, there are one million keys to claim, so get cracking.

SpaceChem has been described as a "design based puzzle game" by the developer Zachtronics, "hard, very hard" by a fan and "This game makes me so mad" by someone with 45 hours play on record.

But hey, free is free.

We'll keep you informed when you can grab Week 2's game, to build your free bundle.