Wow, this is a very special one to review!

To me, it has become one of my favourite games, by far, but it doesn't mean that I could recommend this game to everyone. On the contrary. This is very niche game, exactly the kind of game
that will be boring/weird for the vast majority, but will provide such a great unique experience for a very specific audience. As a result, the real question would be "do you recognize yourself as fitting in this audience?"

- Most people would say :"are you an SAO fan? if yes, then you will like it". To me it's more complicated than that.
Enjoying the anime would definitely be helpful to enjoy the game, but honestly enjoying only the first Arc is more than enough. First because, this is where the game story catches up (and becomes its own thing), and second, because, this game truly focus on the MMORPG theme that SAO is supposed to explore, which is what the first arc is mostly about (and which leads a lot of people wanting more of it). If you are curious about this, you could get at least 20 hours of fun out of the game, and much more if you decide to follow with the all SAO game series.

- But despite its focus on the MMORPG theme (story wise), do you like anime/ JRPG tropes? Because the game is full of it. There are a lot of voiced dialogues, but sometimes, those conversations are very light hearted, not very deep regarding what could somebody could expect from a game. It kinda feels like a teenager gamer slice of life story to be honest, living the everyday life of somebody trapped in an MMORPG. Some people could find that awkward, because of the hard pushed JRPG tropes, but it is also well made for people enjoying this kind of experience. It is overall very uplifting, joyful, and you can end up going to bed with a smile on your face because of the last conversations you had in the game. If you are interested, you could get 20 more hours of fun thanks to all the fun conversations that you will have with the all roaster.

- And the most important point: have you played and enjoyed MMORPG in the 2005-2015 era? Games like Lineage 2 and all of its F2P clones? Games like Wow, Everquest or Aion and TERA? SAO Re Hollowed Fragment is the perfect single player early MMORPG simulator. If you are nostalgic of this time of your life, this game could offer a very unique experience then as it is an extremely rare kind of game to be honest. MMORPGs were pretty barebones and hardcore at the time. You killed monsters, got stronger, to go in harder dungeons, to get more loot, to get even stronger. It was pure grind-based progression while having fun with your friends inside the game. They were much more free, sandboxy, and punishing, there was not time-gating, no battelpass or boring handholding.
If you enjoy learning combat mechanics, ways to get better gear, if you enjoy exploring a huge amount of content at your own pace, setting up your own goals, just like in a MMORPG, if you enjoy grinding for those, you could find this game extremely fun. If you recognize yourself here, you could spend dozens of hours (if not hundreds) having fun exploring and grinding the games content.

Despite its very dated graphics, its cheap budget and the obscure mechanics that could give you a pretty bad/ weird first impression, this game can provide and incredible immersive experience if you happen to be looking for what it does: a love letter to old MMORPGs from the golden era within an anime/JRPG atmosphere.
This game is not a joke. It is definitely not very impressive for a lot of modern gamers, but the only thing that it actually decided to do, it does it incredibly well.