Sub Drop is a fast, challenging puzzler set to launch on the App Store tomorrow, September 17th. The free-to-play title comes to us from Turkish indie developer ScrollView Games.

This is now the team’s fourth game following puzzlers Node Along and Incidence and vertical-scrolling platformer Toxic Hunters. It looks to be another fairly fast-paced puzzler, mixing reaction-based bouncing with rapid-fire subtraction.

The basic idea is that you need to keep a small, bouncy ball inside a spinning square which you have full control over. You’ll fight to keep the ball safe while searching for special numbered blocks.

The ultimate goal in each level is to drop the target points to zero. Each numbered block you hit will subtract from the target number, and you’ll eventually be able to progress to the next stage. That said, you’ll also need to avoid bomb blocks which, when hit, will destroy all other nearby blocks, increasing the chance of your ball falling out of the square.

Based on the trailer, it looks like Sub Drop has the potential to be both relaxing and stressful. The sheer speed of the later levels is sure to challenge even the most advanced puzzle players, and – from reading over user reviews – it seems like the developer has a decent track record when it comes to these sorts of simple, tricky puzzlers.