Abxylute M4 Snap-On mobile controller review: A MagSafe-compatible compact controller

The M4 measures roughly 7.5 x 7 cm and is about 1.5 cm thick. This makes it easily pocketable, but it also presents difficulties for those with larger hands (such as myself). The controller feels cramped and can be very uncomfortable for long play sessions. The layout may not be optimal for some (joysticks at the top, D-pad and face buttons at the bottom), and it can be an awkward stretch for games that require the use of both the shoulder buttons and the D-pad. Overall, it's usable, but longer play sessions left my hands cramping. It's good for a quick 5-10 minute gaming session, but if I plan to game any longer, I reach for another controller. 

The M4 is unapologetically plastic. Since it is designed to be portable, it is very light, weighing in at about 55 grams. The outer matte shell feels well-made for the price, and the body feels more solid than other tiny mobile controllers. Overall, the shell is on par with the 8BitDo Zero 2, which is a good thing.

The inputs are a bit of a mixed bag. They are very responsive and accurate - when playing retro titles like Contra for the NES, diagonals registered perfectly, and the D-Pad works well for fighting games like Street Fighter 2. Inputs registered perfectly well with no ghost presses. However, the D-Pad and face buttons have squishy feedback. I personally prefer crisp, clicky buttons (such as those on the Backbone One controller). The D-Pad in particular feels a bit cheap, but it works well in games. 

The buttons are also quite small, even for the overall footprint of the controller. This exacerbates the cramped issue discussed above.

In lieu of traditional joysticks, the M4 uses circle pads like those one the 3DS and PlayStation Portable. While this creates a flatter profile, the feedback is not great. The circle pads slide into position, which takes a fair bit of adjustment and never feels natural. The choice of these sliders is understandable, but they leave a poor impression. Still, they are perfectly serviceable in games. 

A quick note: I did encounter some stick drift with the left circle pad. However, recalibrating the controller (holding the M, +, and - buttons simultaneously) fixed the issue. It should also be noted that my device is a prototype and may not be reflective of the final shipped product.

The M4 connects to iPhones without issue. Switching modes (e.g., PS, NS) is a bit dodgy and requires forgetting the controller entirely in the phone's Bluetooth settings, but pairing was straightforward. Likewise, pairing it with a Nintendo Switch is free of issues. Input lag is minimal and on par with most other Bluetooth controllers — it isn't bad enough to ruin gameplay, but a cabled controller is preferred for games that require precise timing.

The M4 has on-device turbo functionality. Holding the M button in conjunction with any face or shoulder button toggles the feature on or off. This worked as advertised. L3 and R3 buttons are activated by pressing the M button with either the - or + buttons, respectively. While clunky, this works flawlessly as well.

The M4 has a battery rated at 10-12 hours of use. In practice, I was able to routinely hit about 9 or 10 hours on a charge. The controller charges via USB-C. 

The Abxylute M4 Snap-On aims to tackle an issue present with lots of smartphone controllers: convenience. Most mobile controllers either require the user to stand their phone up from a distance or attach to the phone in a clunky, bulky package. The M4, in contrast, can either be used separately from the phone or conveniently snaps on to its back. It's easy to carry around and whip out for a quick gaming session, making it the most convenient smartphone controller I've ever used.

However, this convenience comes with compromise. The M4 is tiny and, as a result, feels cramped. My hands are large, so I find the M4 too small to use for very long. Smaller hands may find it more comfortable, but it causes mine to cramp up. Additionally, larger phones feel unwieldy on the magnetic ring.

That said, the M4 is a good "grab and go" option if you need something easy to use and easy to carry. It worked with everything I threw at it, from iOS games like Sneaky Sasquatch to emulators like Delta and Retroarch to Nintendo Switch gaming. It will take some adjusting to its small form factor and choice of inputs (particularly the sliding circle pads), but it beats touchscreen controls hands-down and is good for a quick play session.

For $49 at retail, I think the M4 is a bit overpriced. Still, it has found a place in my pack because it is so convenient, but a version with a slightly larger case and buttons would be a better option.