Tim Schäfer’s kvlt-popular headbang-’em-up is totally free on the Humble Store until tomorrow and it doesn’t even matter why because rock ‘n’ roll, baby. Launched in 2009 to somewhat mixed reviews, the game made up for its awkward RTS stuff with some astounding world design inspired by every iconic metal album cover since 1978 and a classic soundtrack including – for the first and last time ever in a game, probably – a song by Rotting Christ.