In my book, a good puzzle game is determined by how well it articulates its gimmick. Portal uses its titular wormholes to mess with physics. Braid lets you rewind time to rework obstacles and perspectives. Return of the Obra Dinn is essentially one sprawling logic conundrum. And Skala, a free puzzle game by Gustav Almstrom that launched on Steam this week (opens in new tab), lets you tinker with scale in order to overcome its 90 brain-teasing levels. What starts out straightforward quickly snowballs into a head-scratching affair, whereby each stage teaches you something new, that in turn informs how you tackle later, more challenging levels. Â
