I would just let people know that, as futile as it might be, if you care about this game or games in general to email Gabe Newell himself. I don't know what other recourse developers have, but it's the least we can do for them. It's just not fair that games like this get denied but they let in so much AI trash or blatantly offensive games. I hate that their review process for games is so arbitrary and that there is no consistency when it comes to a game getting banned. There's no way to know what even triggers the ban and then that's just it. The only time I've seen them reverse course was with Chaos;Head where the community made enough of a fuss and Valve had to save face. So please, if you feel up to it try writing a polite email and doing what you can to help. Thank you and i wish the devs good luck.