The good news, is that we have it confirmed that Linux will be supported, here's what Aspyr Media told us:
We're still coming to Linux, but Early Access will be Windows only. Our full launch should be a simultaneous ship for all platforms.
It's not overly bad news really, since we know plenty of you wait until a full release anyway, but for those who wanted to jump in early it will be a bit disappointing. The full launch is planned to be in the Spring, so it's not a huge wait.
About the game:
Next Up Hero is an impossibly-hard 2D action game driven by Community Continue. Inspired by lost childhoods spent at the arcade in which best friends took turns beating unfairly difficult games, Next Up Hero was created so that beating a level is a shared victory, and more fun than playing on your own.
One to pop back into the watch list, but we will let you know if anything changes on this as development on the game continues.