Ignoring the lack of updates if the game is buggy, games back then were also more focused on quality and make gamers replay the game with unlockable features based on skills, not money. I can't count the number of times I played Metal Gear Solid games over and over to unlock new features playing the hardest difficulty and with handicap features, and also to find Easter eggs. Speaking of Easter eggs, you'd lose a number of hours exploring every nook and cranny finding them!
That was a large part of the charm for me in Tunic. The core mechanic was collecting pages of the instruction booklet as you adventured so you could learn the mechanics of the game. The other part of that being the manual was written in an unknown language* and you'd need to infer what the instructions meant using context clues. It was an absolute blast and hit the dopamine button when I figured out some puzzles.
*Btw, if you know, you know
Oh man, I was coming in here to recommend the same. I'd say to look up nearly nothing about it in order to enjoy the mystery the best.
Sometimes you'd beat a boss, get a manual page from it, and it's like "oh I could've done this the whole time, holy crap"
For any of the Outer Wilds or Obra Dinn fans, play tunic for the mystery. For the ALTTP fans, play it for the combat!