This is a game everyone collectively knows without needing a tard to explicitly recommend it, but I can't leave this thread without recommending Silent Hill. The first one on the PS1.
Much like Resident Evil 1 and 3 (which are also campier but fun recommendations) I can always go back to this game on teh ole PSX. I don't think there are many games (if any at all) that managed to top it as a complete package, this really has it all: atmosphere, a strong driving plot, suspense and mystery, map design that focus on exploration... the only weak point, looking with modern eyes, might be the movement and combat, which is actually still OK, and the graphics, which I'd wager is why many fans of the series praise the second game so much while ignoring the first one.
And speaking of Silent Hill 2, yes it's also a really good game, but I think it's a tad bit overrated as the Silent Hill town feels more like a linear hub interconnecting the levels than the first game, just downtime from A to B while you collect ammo and health... let's remember that in the beginning of Silent Hill 1, on the portion of the town that is initially accessible, you don't go from Bar -> School, you wake up, trace back your steps from the game intro into the alley you walked into before, find out you're supposed to reach Cheryl at the school, and instead of just walking there you try to find a path to it only to find many streets blocked off, and via a hint left on the edge of one of those blocked streets you have to find three keys to unlock the "doghouse house", one in the trunk of a police car, one in the doghouse itself, and one in a basketball court which is really easy to miss since you have to enter a gate in an alleyway to get there. All of that while there's also optional places to enter such as the mini-mart... and that repeats on the other "A to B" sections of the game, you really do explore the town to the fullest extent and even have a subplot with extra story and puzzles that's never hinted at and is missable if you don't give a shit about exploring the last third of the Silent Hill map, a subplot that decides if you're going to get the good ending or not.
In Silent Hill 2 however that's not the case at all, so you lose the whole exploration angle the first game gives you, not to mention the lack of enemy variety, how they're not threatening at all compared to the first's enemies, how the bossfights are not really fun and become bulletspongy to the point of hilarity on Hard (including the corridor chase scene in the hospital that's literally impossible to clear unless you intentionally cheese the Pyramid Head pursuer via melee attacks over and over)... I know this feels like I'm actually reviewing Silent Hill 2, but I think it's cool to compare the two considering the positive bias a lot of people has towards the PS2 entries of the series, it really puts the first game in perspective and shows how underrated it actually is in the point of view of many.
tl;dr: All 4 games are highly recommended but I feel like the first one is the strongest in the whole series, overall, while 2 has the best story and narrative. But yeah, go play 'em. I know I will.
EDIT: oh and btw to make my point about Silent Hill 1 and exploration: did you know you can enter the school bus in front of the school, and inside the bus there are items and a save point? I wouldn't find that out until much later.