The story of Infinite Ryvius is developed well. The plot is fairly basic, a bunch of kids attending a space academy are involved in an accident and get stranded on a space vessel with no adults. However, they do a good job though at developing the story by showing all the ordeals and troubles that the kids go up against and more importantly how they affect each character's state of mind individually. A lot of drama and emotions are involved, there's a good fill of action, and even a nice touch of romance is brought into the mix. So overall, it's a pretty entertaining story to follow. There's just a couple of things that might confuse you in the series as the story unfolds since a lot of it isn't explained thoroughly, but that just means you have to pay attention a bit more.
Obviously, due to Infinite Ryvius's air date, the art isn't exactly top notch. One thing I'd like to point out that I guess falls under the art category too though is that I was a little displeased with the mecha design, the mecha itself just looked kinda blah, unlike most mecha series where you have a really badass looking robot. That's one of my few complaints on the series. Other than that, I can't really complain too much about the animation due to its time.
I found the music fairly impressive. The OP and ED, especially the OP, had a really nice vibe and feel to them that complimented the show well. The background music was pretty good and would always intensify the situation, but luckily you do get that in most series. Same goes for the sound effects. I liked how at the middle of the episode, where it shows the title of the show and where I guess commercials would usually be, they made these cool music mixes, kinda reminding me of Samurai Champloo.
If only the characters designs were a tad better and more special, this would've gotten a 10. The cast of characters is vast, and each is highlighted somewhere throughout the series pretty well. They all encounter a variety of obstacles, and they display and give insight to so many contrasting emotions as the characters develope greatly. Obviously, some are focused on more than others, but to paint the brilliant picture that was painted with so many characters and in just 26 simple episodes, Infinite Ryvius is pretty remarkable in that aspect. All of the characters have a very 'real' feel too, if that makes any sense.
The enjoyment level of this series I would think probably varies from person to person, and what expectations you have going into it. I went into it simply with the desire to watch a decent space drama since I haven't seen much of the genre, and I got what I wanted, in fact I'm now looking into more similar series. But if you're going into this series thinking you're gonna get some awesome mecha action like Gundam, I'm afraid you'll be disappointed. There is action involved, but it is certainly not the main focus. With that said, I feel Infinite Ryvius is a very enjoyable watch because of a lot of the stuff I have already mentioned. The bombardment of emotions, the series of unfortunate events that these kids have to deal with with practically no break, the betrayals, the violence between people, the desperate desire for survival, the new forming love relations, as well as the severing relations, and so on.