Price: £4.99 from fave.co/2AvxulA
Any of the Zachtronics puzzle oeuvre could probably go on this list – SpaceChem, Shenzhen I/O, Opus Magnum, and probably even Infinifactory. TIS-100 is one of my favourites though, and about as low-impact as you can get. Designed to feel like programming an early computer, TIS-100 does the usual logistics-centric Zachtronics puzzles by way of faux-Assembly code, complete with an out-of-game manual that I heavily recommend printing out and keeping nearby. Hell, go full 1980s and stash it in a three-ring binder.