This game is only as high as 2 stars because the fighting game gameplay is mostly unchanged from the previous X games.
Not much is different, but there is 2 new modes, GG Boost and Versus (4-player). I could not get past stage 1 of GG Boost, it was awful. I played a bit of the 4-player versus, which seemed mostly fine, but I had no interest in continuing.
This game features no story, but it introduces A.B.A (as well as Robo-Ky Mk II, but, whatever), which is a shame that she was introduced of this slop.
I don't have much to say, I played like 15 minutes of this game before saying no and deleting it. I didn't want to play through the side scrolling adventure any longer.

A nice follow-up to X, and probably, most definitely surpasses it.
The story of this game is very simple, I-no wreaks havoc, and hijinks ensue. Because of this the general plot is a lot more expanding, and there are much more subplots behind the main one, as well as the assassin's guild plot. There were many interesting reveals, and I enjoyed the additions of the new characters. Slayer is a great addition, Zappa is interesting, Bridget is cute, and I-no is mysterious. I also loved the addition of all the Robo-Ky's, it added great tension to some of the character's endings, for which there are 3 for each individual character. It's also all voiced, a great improvement toward X Plus!
I may be wrong here, but the gameplay to me feels very similar to X. It features the same sprites, attacks are the same, the only thing I could only tell was different was the voicelines. The new characters feel great, but there isn't much to say compared to what I had to say when comparing X to the original.
The character's themes also sound the same from what I could tell, maybe I'm wrong, but that doesn't mean they were bad. Like all Guilty Gears, the music is great! I especially like the ending themes, of course.
Overall, there really isn't much to say. It's X with some new characters, and a neat new story. This is only part 1 of 2 though, so I have to wonder how little I'll be able to say about the next (main) installment as well.

This game is a huge step-up from the first, and while not perfect, it's a game I can see myself returning to. It's more than I can say for the original.
My biggest complaint is with the story, or I guess you could say the lack of one. Like the original game, it features no story mode, and the arcade mode is what you use to experience what story there is. Unfortunately, however, the way this game goes about this is somehow worse than the first game. The winning quotes feel much less specific, and when you finish the thing, nothing is shown but one piece of artwork and credits, leaving you to simply assume what just went on. I thought this was super lame, and was baffled how there wasn't even dialogue exchanges near the end like the first game did. Luckily, the japanese-only updated version "Guilty Gear X Plus", DOES feature a story mode, and delves deaper into each character's stories, and it's great! I especially loved Dizzy (she deserves the world). Sadly, I'm not reviewing that game, so it leaves this particular version's story rather lackluster.
The gameplay is where this game really shines compared to the original Guilty Gear's. Everything has been improved, and it all feels much more balanced. Every character felt fine enough to play as, and one didn't seem a lot better than others, which is a great step above the first. Instant wins are also removed! Or at least, ones that don't win you the entire match. The moves feels smoother as well, and I found myself using overdrives a lot more often, it just felt much more fun. There was also the addition of difficulty options, which was great my newbie self. The updated graphics during the battle was also stellar! The pixel art is so freaking nice, it's very fluid snappy and helps make the gameplay more satisfying.
Along with the gameplay, the music felt more catchy and has definitely seen an improvement too! The ending themes are wonderful, the battle themes were good, and I loved Dizzy's pre-battle theme (I'm not really sure what to call it?).
It's odd, when I first played this game, it was like a swing of both love and disappointment. I cheered for the better gameplay and wonderful art, but then got disappointed for it's lack of story, but then understood the gameplay more, and found myself enjoying it quite a bit. This game was a major improvement for Guilty Gear, and I can't wait what the next game has in store!