Headup games announces TRISTOY, a co-op 2D platformer coming to Steam on January 15th. This trailer shows off gameplay, including an unusual dynamic split-screen implementation, as this apparently requires two players. Here's the announcement:

Headup Games and Merge Games today announce TRISTOY, a story-driven 2D-co-op platformer designed from the ground up exclusively for two player co-operative gaming enjoyment!

Set in Tristoy, an ancient fortress in the middle of the Sea of Shards you play together as Prince Freedan and the Wizard Stayn. You and a friend must team up to try and escape the dungeon and defeat a common enemy, the witch Ink.

Explore dungeons filled with traps and monsters - puzzle, jump and fight your way out as you attempt to escape from Tristoy. Designed to be played together on one screen, Tristoy’s engrossing non-linear story features multiple endings and requires you to work together, testing your friendship and forcing you to confront moral dilemmas and make some hard choices.

Developed by German studio Uniworlds Game Studios, the game features a dynamic split screen, which moves, rotates and seamlessly joins back together, keeping you locked in the action. Play with a keyboard, controller or use your smartphone to control the game with the companion app.