Gamescom Day 2 Round-up - what impressed us most?

Day 2 of Gamescom is at an end. It's been crazy, too - the showfloor is open to the public and there are cosplayers and sweaty gamers everywhere. But we've been away from the throng, behind closed doors and playing things that have actually blown the fragile mind of PC Gamer's Owen Hill. What could it be? Clue - it sounds a bit like a Harry Potter spell gone wrong...