Decidedly not arcade, but I absolutely love Shattered Pixel Dungeon as a phone timekiller.
UPS depends on usecase and on the stability of your electrical supply (which varies greatly from place to place). I just leave everything running and have it configured to restart automatically on power restore (if it fails, which it rarely does).
Haven’t they recently renamed “My Computer” to “This Computer” on the desktop?
Rockbox can be installed to mitigate that. And the hard drive can be swapped for bigger flash storage, which also has the positive effect of leaving more room for extra battery.