Grumz is the first effort from the Toronto-based Picnic Game Labs, and the new mobile title (which is currently available via the Apple App Store and Google Play) is like an infinite runner in reverse. With a spacey soundtrack and a minimalist visual aesthetic, the game places the emphasis squarely on gameplay while eliminating (most of) the garish marketing clutter that afflicts other mobile titles. The result is fun and disposable, a simple-to-learn-yet-hard-to-master distraction that reflects the best and most addictive aspects of mobile gaming.

So what is Grumz?

For the lack of a better term, Grumz is an infinite stopper in which you control a spinning disco ball that bounces from the top to the bottom of the screen and back while travelling on a fixed axis. It’s a bit like controlling a spinning buzz saw in a platformer like Super Meat Boy or Mario Maker, with the caveat that the threat of danger has been reversed. You don’t have any spikes and you’ll die immediately if you get hit by any of the various objects that blast across the screen.

Those objects take the form of geometric shapes that each have a different property. Cubes, for instance, appear and then stop before launching themselves at high velocity, while missiles travel through a portal to attack on a separate, parallel plane. Figuring out those movement patterns is one of your biggest challenges when you first start playing.

The primary challenge, however, is avoiding the Grumz, the technical term for the shapes that crisscross the screen like an invading alien army. You get a point for each trip back and forth, but you can’t fight back in any meaningful way. You can only stop, which you do by tapping the screen and then holding it to stay in place (you’ll start moving again as soon as you release your finger). The goal is to stop just long enough to let traffic pass, making the whole thing play out like a digital blend of Frogger and Fishy Fishy Cross My Ocean.

And that’s pretty much it. You go up and down like a mirror ball on New Year’s Eve while trying to avoid the objects bombarding you on all sides. There are enough shapes and power-ups to give the game variety – the power-up that makes you temporarily invincible will let you complete a lot of trips very quickly – but the core mechanic is incredibly simple and makes Grumz an accessible, intuitive choice for anyone looking for a solid mobile diversion. It’s a great way to pass the time while in a waiting room or in transit, which is probably how it will fit into most people’s lives.

It helps that Grumz boasts much better game design than the average mobile title. The timing is exceptionally precise, at once minimizing luck and rewarding focused play. The game isn’t selling power-ups or pushing microtransactions so the gameplay is more balanced than mobile games that hide progress behind a paywall. You’ll get exactly the same game experience every time you play, and your performance is based on your ability rather than your willingness to spend money.

The game does have some irritating hardware limitations. Sometimes the Grumz will hide beneath your fingers while you’re stopped, in which case they may crash into you before you’ve even registered that they’re there. That’s more of an issue with iOS games in general than it is with Grumz in particular, but Grumz is an unusually fast-paced game so the issue is more noticeable here than it is in other titles.

Thankfully, it’s also not a deal breaker. Grumz is refined enough to be predictable, even when things appear at random. You can generally be sure that something is trying to kill you and slowing down (literally) should give you the time needed to process obstacles.

Grumz is free to play, but it is ad supported so you’ll have to sit through a commercial after every third attempt. However, you can pay a one-time fee of $1.99 to unlock the full version of the game. It’s definitely worth it if you find yourself playing regularly. The game is still enjoyable with the ads, but they are obnoxious considering that it only takes a couple of seconds to jump back into the game under normal circumstances. Getting rid of the ads eliminates those interruptions and improves the feedback loop to ensure that you’re always playing rather than sitting through a sales pitch for a digital slot machine.

I’m not going to oversell Grumz. It’s a diversion and I won’t pretend otherwise. But it has enough complexity to keep you engaged for longer periods if you so desire. Though the game can be difficult – a score of 50 is a solid run and the overall experience is reminiscent of a slightly more forgiving version of Super Hexagon – it’s satisfying in small doses and a fine addition to the catalogue of time wasters that currently occupy your phone.