The basic premise is that this is an American-made Ecchi Visual Novel about a school for those with disabilities. The Main Character, who you play as, has a heart condition,specifically 'cardiac arrhythmia and congenital heart muscle deficiency,' and qualifies him for the school. The game takes place over a full year, and you're given the chance woo one of 5 girls with various disabilities.
If that description sounds like the should be a disgusting mess of a representation about the disabled... You'd actually be wrong. This game has a very strange history which honestly makes it even more surprising in some ways that it's not exploitative. The game was brainstormed on the infamous message board / forum 4-Chan, at first as a concept and various character designs to my understanding. But then the game designers and artists and everyone else who gathered together (I'm quoting from memory after a brief wiki glance for the heart info,) sat down and made a relatively serious game that doesn't gloss over any of the issues involved.
As an added bonus, the creators of the included the ability to turn off the more adult (as in sexual,) content, so that would make it easier to adapt to GOG. I definitely reccomend this game.