To try out the game, you need two instances of the game, as this is a multiplayer game. Of course, the best approach is to call a friend, but you can also run the game twice and click Play. That's it. Or if you want to run the server locally, in the GitHub repository there are instructions for that too. Enjoy!
About
Biome Fighters is a 1v1 online multiplayer platform fighter game with a retro aesthetic, where there are more than just two platforms and every corner is an opportunity for the victory. It is inspired in Spelunky's deatchmath, but taken to a competitive online multiplayer environment.