Maybe Antichamber? It‘s a first-person puzzle game like Portal, but based on the idea of the „rooms“ changing as you go through them, so each room basically has its own mechanic to figure out

Sadly not as AFAIK you need to be connected to the same network as the device (at least on iOS)

Mine was a Raspberry Pi in the early 2010s - I‘d had relatively little experience with computers before and had no idea what a terminal was (or even Linux for that matter, tbh), so it took me a good couple of weeks to even figure out how to reach the desktop… Used Windows most of the time after that, but got back into Linux via Ubuntu a couple of years ago. I‘ve now switched to Fedora as my daily driver and wouldn‘t go back either :)