Also the PS1/Saturn version has no battles in the overworld (you just move around with no opposition), completely redesigned overworlds and dungeons, visible enemies in the dungeons/zoomed-in field areas (and more of these to make up for the missing overworld battles, I think), there are now some simple puzzles in some dungeons but dungeon layouts have been made simpler (less mazelike than on Sega CD), Luna joins your party up until the point where she gets kidnapped (that happens at the same time, though), there's a bit more fanservice, more cutscenes and voice acting, and probably more. Lunar for PS1/Saturn isn't a port, it's a remake. I like the Lunar 1 remake better than the SCD version; playable Luna is a particularly nice addition. Having no battles in the overworld is unfortunate, and the dungeons definitely aren't as complex, but I really do like the additions. And at least the PS1/Saturn dungeons have some complexity; the GBA and PSP remakes simplify things even more. The PSP one goes way too far in that regard, I think... it brings back the original battle system (the GBA version removed it in favor of a generic "two lines of people attack eachother" thing), though, which is good.
Lunar 2 for PS1/Saturn keeps most of Lunar 1's changes, but it's a bit less different from SCD Lunar 2 because the plot hasn't been changed much; there are some minor changes, but nothing as big as the first game. Also SCD Lunar 2 actually has MORE cutscenes than the remake, though the remake makes time to add a second bath scene just because. I like the visible enemies, but otherwise the Sega CD version is better. Gameplay-wise the changes are pretty much the same as the first game, of course -- it's got a bit less dungeon complexity and no overworld battles, but great visible enemies and some puzzles. The story changes in the remake are minor, but they kind of mess up Lucia a bit, which was annoying. Still, I know it might be being inconsistent to like the first one better on PS1/Saturn and the second better on Sega CD, but I do. It's probably because I clearly prefer the opening section in the first games' PS1/Saturn version to the original, while there's no part of the second game like that.