The C64 Mini is a shrunken-down version of the original, although its keyboard and casing is just for show. Basically, it's a hunk of plastic that's been cut and painted to look like the real deal, even if the icons on the underside of the keys are missing. If you aren't planning on using it as a working machine, it could easily pull double duty as a paperweight.
Beneath that exterior, I suspect, is a dinky miniboard, like a Raspberry Pi, that's running an emulator. That would explain the closeness of the two USB ports that run where the C64's serial ports originally sat and the micro-USB (power) and HDMI-out ports. The original model had the power and video-out connectors far further away, so clearly there's a reason for the change.
Also inside the box is a micro-USB-to-USB cable and a HDMI lead, and I'm sure some will be upset that there's no power adapter. That said, most HDTVs have a powered USB port, and you probably have an old smartphone adapter laying around somewhere. A nice touch is that the manual's cover is styled to mirror that of the original CPC 64 documentation.
Rounding out the bundle is a remake of the Commodore 64 joystick, with extra buttons and a USB connection. It is, unfortunately, stiff and often unreliable, with gameplay suffering because of it. I needed to ram the palm of my hand into the stick, hard, if I wanted even a hope of my character going in the right direction. I won't share my notes here, but there were more than a few expletives included. It may loosen over time, for sure, but I doubt the accuracy will improve much.
The C64 Mini's OS is designed like a carousel, and it takes less than a second to boot up from cold. Essentially, the lower half of the screen is the box art for each game that you can move left and right between. Above it, the left side holds a still and/or footage from the game while the right offers a brief synopsis of the game.
There are 64 titles on the system, although you may be surprised and disappointed to learn that plenty of notable games are absent. I suspect licensing issues precluded the inclusion of titles from major publishers like (then) Lucasfilm Games, Origin and EA. If you were hoping to play Zak McKracken, Maniac Mansion, Pirates!, Ultima, Wasteland, Skate or Die or Elite, you're out of luck.
I want to be honest and say that your mileage may vary and that the titles preloaded onto the C64 Mini could be cornerstones of your childhood. In the days before the internet and monolithic games publishers, it was much easier to miss titles that didn't pop up in your local store. But even so, it feels like the game selection here is the leftovers from a dumpster dive rather than a curated experience of the "best" titles the platform had to offer.
The biggest names in the roster include Impossible Mission and its sequel, Speedball, and, uh, its sequel, and Paradroid. Sports fans may also get a tickle out of Summer Games II, Winter Games and World Games, which I dimly recall being forced to sit through as a kid. Memory plays tricks on us all, however: I thought I had fond memories of Who Dares Wins II, another included title here. After playing it and doing some research, it turns out that I'd actually played Commando, of which Who Dares Wins was a fairly shameless copy.
Retro Games clearly knows that this is an issue and makes a big deal about the fact that you can sideload other titles onto the system. The usual copyright caveats apply, but the only thing between the Mini and downloading a bunch of .D64 ROMs onto a flash drive is your conscience. Although it's worth noting that you can only load one title at a time, and you have to do it in BASIC.
Actually, it's harder than that, because my generic Windows USB keyboard wouldn't navigate the C64 Mini's carousel menu. You need to use the joystick to activate BASIC and then switch to the keyboard to type the commands necessary to load the game. Except the C64 Mini only has two USB ports ... So you pull out the joystick to make room for the flash drive, right?
As soon as I pulled out the joystick, the console reset itself back to the carousel, so the only way to do it was to type with the virtual keyboard. The solution to this is to use a keyboard with integral USB ports or a standalone USB hub, but at this point I wondered if it was worth the effort. Retro Games has promised that an update will make this process easier in the future, but when that will happen is anyone's guess.