Despite fighting games being one of the toughest genres to develop, especially when it comes to indie efforts, it doesn't seem to deter the countless passionate developers in the fighting game community.
The latest proof of this is the "Untitled Risk of Rain Fighting Game" from AHamUWU. People with extreme ball knowledge might remember them as the developer behind "Hypothetical Horse Race Tests Fighting Game."
This one was also made in Fighter Maker 2nd, and features 18 characters with 8 alternate versions. Naturally, both the characters and stages are based on Risk of Rain, with character abilities being adapted into the fighting game format.
Early responses from people who tried it look really positive, but it's not without some technical issues, as some players have problems with the input reading or even installing the game in the first place.
You can also play this one online thanks to LilithpPort, which is a program designed to enable multiplayer for pretty much anything made in Fighter Maker 2nd.
If you want to pick up the game, it's absolutely free over at Itch.