After the meetings of the day at Gamescom, I found this 2.5D arcade adventure where you play as a knight who turns into stone if he doesn't kill enemies and find certain items. The game looks like a side-scrolling version of the original Dark Souls. The developers were awfully friendly, and I ended up playing several levels of their game.
Screenshots marked with 🍒 are created by syltefar and are considered public domain, free to use for anything. If you want to, you can note where you found it and link to this page.