This is the one and only Breath of Fire game I've ever played, weirdly enough, and I made it almost all the way to the end before I lost track of the disc. Despite my not even barely having scratched the surface of everything there was to do in this game, I still remember it incredibly fondly for its unique, complex story and that absolutely luscious pixel art - so once I spotted it on the GOG store I happily bought it (again) to get the more complete experience as an adult. What we have here is effectively a one-to-one port of the original with minor and unintrusive quality of life updates to smooth out the "90's/early 2000s RPG" edges that came from the genre being way more experimental back then - and even with those qol features it's still the grindy timesink you know and love if you played the original, with the slight added jank of trying to accommodate for mouse and keyboard controls. If you HAVEN'T played the original, or any of the other classics from that time period, be aware that this is much more of a time and energy investment than a lot of modern turn-based RPGs, and a lot of that invested time involves "busy work" to prepare for not getting completely pasted against the nearest wall by whatever boss was up next. Regardless, this game is really something special and is a fairly faithful time capsule of the original experience, so if that sounds like something you're looking for then I highly recommend it.
My memory of the original game has gotten foggy over the years but as far as I can tell from the stages I've played through, G.O.R.E is functionally identical to the originals: you run through hallways cluttered with destructible debris and equally destructible enemy hordes, and smash the attack buttons until you get thumb blisters or there's nothing left in the stage to blow up. There's even an option to apply a cel-shading filter to mimic the look of the first two games on PS2 (though it doesn't apply to cutscenes). The story drops you in like it's the latest season of an ongoing show and just assumes you've watched the previous episodes - there's a very rudimentary explanation of what's going on, but it's set up with the idea that you've played the original games or at least watched the anime, so if you like your shooter/brawlers to have a good cinematic narrative that's easy to follow, this will be a letdown. Additionally, the elaborate designs of characters returning from the original games - made by the creator of Trigun, Yasuhiro Nightow - clash pretty hard with the more grounded, almost Saints Row 2 aesthetic they're using here, but you spend most of the game staring at Grave's ridiculously huge shoulders anyway. The game runs soundly, if not smooth. I have had difficulty navigating Grave around certain areas since he's about as agile as a lead brick in a black hole and struggles with getting caught on walls or boxes and thus cornered by swarms of enemies, but you get access to a special skill that staggers and breaks enemy shields, AND restores your health, so as long as you manage your energy resources well you can just bazooka your way out of most problems. It's repetitive, but weirdly satisfying. Overall, this likely won't appeal to younger generations of players who grew up with higher quality action games like DMC5, but for the early 2000s anime crowd this is basically one long, silly flashback.
