The nigh-unpronounceable rymdkapsel ($3.99) is equal parts Tetris tower defense, a premise that I realize makes absolutely no sense. It’s good though, so bear with me for a minute.

You’re tasked with building a space station out of rooms constructed from romly selected tetrominoes, juggling resources exping to explore the galaxies. It’s the brainchild of grapefrukt games, is a genre-bending treat that deserves your attention.

The controls are simple: just drag drop bits around to build rooms assign tasks to your minions. Corridors serve as a sort of arterial network, linking rooms allowing your minions to travel about, hauling resources or getting some construction done. The reactor produces energy, while an extractor harvests building supplies from nodes strewn about the map. There’s also a garden that produces sludge, which you’ll convert into food at a kitchen. You’ll also need to build quarters supply them with food, to add new minions to your ranks.

It all feels rather manageable, until you realize you’ve walled in your corridors, leaving no room to exp acquire more resources. Or worse still, you’ve stretched yourself a bit thin it takes forever for your subjects to trot about your compound. And then, the alarms sound: once the red bar running along the bottom of the screen fills, a wave of enemies pours in takes potshots at your troops. Building a weapons room will let you arm two of your minions to serve as sentries, albeit with limited range—you’ll want to be sure to sprinkle these defensive structures liberally. The game’s only goal is to survive the increasingly difficult waves of enemies, exploring the galaxy unearthing the secrets behind massive monoliths scattered .

Up for the challenge? rymdkapsel will set you back a measly $4, you can grab it on the Apple App Store ay.