You know where this is going and you knew if anyone would make this topic, it'd be me.
So yeah, this is the topic all about those games that you played and enjoyed as a kid, re-acquired or replayed many years later as an adult expecting to enjoy the nostalgic memories... and then you realize that game you enjoyed as a kid is in fact a horrible pile of badly-designed shit and you regret picking it back up and ruining the nostalgia forever.
It should be no surprise that the two games that come under this category for me are Heretic and Dark Forces. I loved the former as a kid and after replaying its sequel Hexen as an adult and loving that just as much as when I was a kid I couldn't download Heretic off Steam quick enough... and then I started playing it. Same story with Dark Forces almost except I didn't like it as much as Heretic as a kid, and hated it a fair bit more as an adult.
So why did I suddenly dislike them? Simple: Their design was annoying and genuinely bad at times, and as a kid I didn't really have the awareness to realize they were so bad. Heretic somehow manages to make a ton of different mistakes throughout its levels that include but aren't limited to putting lava rivers into ice levels, putting monsters in rooms that are the exact same colour as they are so you can't see them, horribly positioned monster closets (the most ridiculous example being a closet placed behind you when you spawn into the level that opens the moment you move,) very poorly-hidden secret levels, placing level exits behind ridiculously-placed secrets and dumping boss monsters into the level exit rooms throughout the entire of Episode 3. All in all it makes for a game that's just annoying rather than challenging and you feel like you're fighting the game's bad design more than the enemies. Also, the weapons are shit (one weapon has a muzzle flash that blinds you for example) and the inventory system is even worse (you literally can't use items in the middle of a fight due to how badly designed it is) so the shit design isn't just limited to the levels. I could go on for days on end about everything wrong with Heretic because there is far more than just this wrong with it, but I'll leave it at this.
Dark Forces, as I said, managed to be even worse. There's far fewer issues with this game, but the issues it does have are much more problematic. Ridiculous level design in several cases (figuring out Level 3 is near-impossible outside of figuring it out by pure accident or using a guide, and that's just one example,) absolutely disgusting graphics in the levels (apparently no-one told the level designer that, yes, you can use more than one colour per level) no save feature (the game gives you lives instead - run out of lives and die? Repeat the entire level...) and the Prison Complex level manages to literally be Daikatana: Dark Grey Edition due to featuring all the same problems as Daikatana's infamous, bright-green starting level (same colour issue mentioned earlier, explosives having far larger hitboxes than their explosion graphics, weapons that often do as much damage to you as to the enemies etc etc...) which makes it seem rather hypocritical that Daikatana gets slagged on for being terrible but Dark Forces is considered a classic despite, minus game-breaking glitches, doing the same terrible things Daikatana did (worse in some cases - at least Daikatana let you save mid-level even if it did limit the number of times you could do it.)
So there you go, now you can post your games that you enjoyed as a kid, replayed again to enjoy the nostalgic memories, and got nothing but a kick in the teeth and shit game design for it.
So yeah, this is the topic all about those games that you played and enjoyed as a kid, re-acquired or replayed many years later as an adult expecting to enjoy the nostalgic memories... and then you realize that game you enjoyed as a kid is in fact a horrible pile of badly-designed shit and you regret picking it back up and ruining the nostalgia forever.
It should be no surprise that the two games that come under this category for me are Heretic and Dark Forces. I loved the former as a kid and after replaying its sequel Hexen as an adult and loving that just as much as when I was a kid I couldn't download Heretic off Steam quick enough... and then I started playing it. Same story with Dark Forces almost except I didn't like it as much as Heretic as a kid, and hated it a fair bit more as an adult.
So why did I suddenly dislike them? Simple: Their design was annoying and genuinely bad at times, and as a kid I didn't really have the awareness to realize they were so bad. Heretic somehow manages to make a ton of different mistakes throughout its levels that include but aren't limited to putting lava rivers into ice levels, putting monsters in rooms that are the exact same colour as they are so you can't see them, horribly positioned monster closets (the most ridiculous example being a closet placed behind you when you spawn into the level that opens the moment you move,) very poorly-hidden secret levels, placing level exits behind ridiculously-placed secrets and dumping boss monsters into the level exit rooms throughout the entire of Episode 3. All in all it makes for a game that's just annoying rather than challenging and you feel like you're fighting the game's bad design more than the enemies. Also, the weapons are shit (one weapon has a muzzle flash that blinds you for example) and the inventory system is even worse (you literally can't use items in the middle of a fight due to how badly designed it is) so the shit design isn't just limited to the levels. I could go on for days on end about everything wrong with Heretic because there is far more than just this wrong with it, but I'll leave it at this.
Dark Forces, as I said, managed to be even worse. There's far fewer issues with this game, but the issues it does have are much more problematic. Ridiculous level design in several cases (figuring out Level 3 is near-impossible outside of figuring it out by pure accident or using a guide, and that's just one example,) absolutely disgusting graphics in the levels (apparently no-one told the level designer that, yes, you can use more than one colour per level) no save feature (the game gives you lives instead - run out of lives and die? Repeat the entire level...) and the Prison Complex level manages to literally be Daikatana: Dark Grey Edition due to featuring all the same problems as Daikatana's infamous, bright-green starting level (same colour issue mentioned earlier, explosives having far larger hitboxes than their explosion graphics, weapons that often do as much damage to you as to the enemies etc etc...) which makes it seem rather hypocritical that Daikatana gets slagged on for being terrible but Dark Forces is considered a classic despite, minus game-breaking glitches, doing the same terrible things Daikatana did (worse in some cases - at least Daikatana let you save mid-level even if it did limit the number of times you could do it.)
So there you go, now you can post your games that you enjoyed as a kid, replayed again to enjoy the nostalgic memories, and got nothing but a kick in the teeth and shit game design for it.