There are a lot of 40k freebies at the moment (it seems to be how they generally advertise their new games), I saw this one posted elsewhere and it's something a bit different

Type like your life depends on it in Warhammer 40,000: Boltgun – Words of Vengeance! Smite the enemies of the Emperor with every keystroke spelling their demise. But every typo could mean the difference between life and death.

The Mechanicum of Mars have gifted you a blessed new weapon - a keyboard! Brutally decimate hordes of daemonic scum with every keystroke, in this fast-paced rail shooter. None can stand against the might of your WPM!

Warhammer 40,000: Boltgun - Words of Vengeance is a creative twist on epic boomer shooter Warhammer 40,000: Boltgun. Instead of mowing down your enemies with elite FPS skills, kill the relentless hordes of enemies that descend upon you by typing out words.

Set in the world of Warhammer 40,000: Boltgun, play as Malum Caedo on his mission to cleanse Forge World Graia of cultists, traitors and Chaos daemons that threaten to overrun it.