So insert credit, and later Gamasutra, was the primary destination for a lot of this information because a certain person was interested in it - I don‘t have the present brain space to get into all of it but here’s what I‘d like to talk about if anyone wants to take up the baton after I list them. I’ll try to come back in and add info later:
Antman 2 - namil soft - this was directed by Hakkyu Kim, later of Ragnarok fame, and is something of a gunstar-like for PC in 1997. he doesn't even have a copy, just a box that his mom found at a flea market.
Lars the Wanderer - a side scrolling action RPG also from HKK, published by gravity pre-ragnarok.
Corum series - offline RPG diablo-like that was really good. I played Corum 3 a lot.
Astonishia Story - pretty well known compared to many. An RPG with great lush animation from sonnori, which got ported from DOS to GP32, then to PSP. Crimson Gem Saga is the pseudo sequel, also on PSP.
Her Knights - a small series from Byulbram, starting with an RPG on PC, then a beat-em-up on GP32. Pretty well regarded all around.
Asura Cross - an interesting fighting game also from Byulbram with a unique approach to movement and special attacks.
Dynamo Beast - another byulbram creation, this time a multiplayer tank thing that has a very Kokuga-like feel in its deliberateness.
Kimchiman - not great, but it's a platformer starring a kimchi superhero. had both boxed PC and GP32 versions (I have a sealed PC version for some reason)
Tomak - the first game was a visual novel starring a head in a pot - a princess/goddess who wanted to save the world by proving that love could exist even if she didn't have a body. PC, then ported to PS2. Then after that came Tomak save the earth, which is a GP32 shooter.
White Day - honestly the remake really focused how not-great the game is now, but back in the day it was a somewhat unique approach to survival horror on PC.
Manic Game Girl - a rent-a-hero-like that's not very good but is all about a heroine with a game boy who goes around doing good deeds and grinding for exp. The only(?) Korea-only PS1 game.
Psyvariar - stg series originally made in Korea, though now taken over by the publisher, success. Or was only the second Psyvariar done in Korea? I can't remember now. Either way, I did a meeting with Sony for them when their translator couldn't come, they spoke to me in japanese, their second language, which I then translated into english. It was ridiculous because sometimes they'd slip back into korean and I'd be like guys, you're speaking korean again.
At this point I feel like Audition, DJ Max, and Pump it Up are retro games too, but that feels a bit weird to say.
Anyway - there's a lot that's not so good in the korean retro game scene, but there's some real gems in there that are worth unearthing, many more than I know about I'm sure. But so few people, even in Korea, pay attention to the pre-F2P era that it's hard to find information.