Spoiler free syonpsis: a bunch of space cadets become stranded on a massive warship while evacuating their disintegrating space station; order breaks down because the top cadets can't keep the rest of them in line while they try to find their way home, and it turns into Lord of the Flies in Space.
It started off strong, but midway through I just hated it. Loathed it. Something deep in my gut said, "This is a terrible, awful story."
When you tell a story like this, a story that makes you hate all of the characters, there's gotta be something worthwhile tucked away. Some little spark of hope or redemption that makes it worth-while. Infinite RYVIUS has none of this. Nothing. During an encounter with a hostile space-ship, I suddenly yelled "FUCK YAH!" when I thought the enemy space ship was actually going to sink them. That's how much I hated the whole thing.
But, being how I am, I ended up watching it through to the end. There's a happy ending, but it isn't enough to make the anime taste like anything other than goddamn awful.
So now you know: when I start rambling about kids and space and hoping the whole goddamn ship blows up into a million pieces, you'll know what I was talking about: Infinite RYVIUS.