I played Ultima V without any documentation. I had to decipher the rune language, draw the overworld map, map the moongates, and figure out the spell reagents through trial and error, not to mention the basic keyboard commands (I rowed frigates for the longest time before I figured out how to unfurl the sails). On top of that the game requires all sorts of book keeping: detailed notes of conversations, including key words (the password is "dawn"), coordinates of locations using the sextant, and mapping all the dungeons. There was probably a bunch of stuff i never figured out to do (like level up, was it random at every camp out?) I finally gave up when I reached the underworld, I mapped what I could but there were mountains I couldn't get past. I think i found out years later that I needed the blink spell, and since I only figured out spell chants through trial and error (Grav Por!) that would have been very difficult (but so was everything else up until that point).
It was totally worth it, the open conversation system, true sense of exploration, the risk reward to deep dungeon diving, and my own satisfaction at figuring stuff out. And the narrative was told so effectively in game, like when I was captured by blackthorn and had to choose whether to reveal the password of the resistance or sacrifice one of my party.
I would never play anything like that again.