First off, Lux-Pain is what's known a 'visual novel', an interactive story often including moral/conversational choices that the reader can make for the primary character. To use a Western genre, this would be a point and click, so if you're looking for something with fight mechanics you're in completely the wrong place.
Lux-Pain is a pretty good game. The story's interesting and although I wasn't too sure on the 'slice of life' school based parts of it at first, I soon found that all the characters are interesting, funny and well-developed enough to make them worth it.
However, the dialogue can be pretty hit and miss. It's absolutely clear that the translators for this game were either not paying attention or weren't particularly good at English. There's quite a few mix-ups between 'he's' and 'she's', some words are spelt incorrectly and words such as numbers are often abbreviated or hyphanated in the middle of a word which looks horribly tacky.
BUT, the voice ators do go a long way to make up for this. Most of them ignore the exact words put in front of them to read and have produced their own version, and they've done a good job despite it not matching the text onscreen. The voice acting sounds unique to each character and very realistic, not the run-of-the-mill monotone a lot of other translated JRPG games have. But the game does lose points here too for having very few scenes narrated, and having some characters not even given a voice at all.
The game is interesting, the plot is good. It will only tax your decision making, so it's a great game to relax to. If you can ignore the bad translation and want an interesting story, give Lux-Pain a go!