Wikipedia says it best:
"Katawa Shoujo (かたわ少女 (Katawa Shoujo lit. "Disability Girls" or "Cripple Girls"?) is a bishoujo-style visual novel by Four Leaf Studios which tells a story of a young man and five other girls who have suffered different disabilities. This game uses a traditional text and sprite-based visual novel model with an ADV-style text box. Katawa Shoujo contains adult content, and is created using the Ren'Py visual novel engine. While the demo contains no such content, the full version will contain an option to skip all scenes containing sexual content.[1] As of now, only the demo has been released. The release of the full version has yet to be announced,[2] The demo is licensed under the Creative Commons CC-BY-NC-ND[3], and the same is planned for the full game."
Now, while the concept may seem questionable, execution is really, really good. The writing is a bit rough on the edges sometimes, but it's generally good, and it deals with the themes of disability in quite an admirable way. Give it a chance, it's woth it.