Over the last year I’ve immensely enjoyed Dread delusion and lunacid. Both of these are deliberately emulating a style of game from my childhood, however they include the playability of modern games: UI smoothness, rebinds, graphics options, modern tutorial design and so on.
I have found these very engrossing games but they are also relaxing mentally. They’re not very difficult (although lunacid is punishing of failure it’s easy to execute) and the gameplay is simple and obvious. The delight comes in the aesthetic polish drawing me in to mysterious alien worlds.
When I think of simple and very playable games, the sort you don’t have to consult a wiki on or invest ages learning, mostly what comes to mind are the modern trend of roguelite arcadey games which tend to be very difficult and very exciting.
If you’re after something different I’d wholeheartedly recommend these two and I’d also like to beg for anyone’s recommendations for simple/playable exploration centric games while I’m at it.
Virtual Hydlide, though you need to look up the mechanics/tips briefly before playing. It’s otherwise a pretty straight-forward fantasy RPG with OK exploration. King’s Field/Shadow Tower games too, though maybe just the PS1 games. Not sure if the later ones get complicated.
I remember the DS/PSP had a bunch of straight-forward 3D dungeon crawler games like Dungeon Siege, although maybe they had complicated loot 'n grind systems I’m unaware of, but that era of handheld RPGs seems prime for exploration-based RPGs without stupid amount of mechanics. Maybe the portable Phantasy Star games too on DS/PSP, etc. 3DS too, probably, with like Ever Oasis and stuff. Actually, probably Wii too with stuff like Fragile Dreams, Final Fantasy Fables, Rune Factory, Opoona, etc.
Also maybe fantasy FPS/RPG-FPS games like Hexen, Heretic, etc. They’re pretty straightfoward and pretty fun with okay-ish worlds to explore.