If you're after a rather challenging looking shoot 'em up you've come to the right place, as Zeon 25 has Linux support and it just entered Early Access.
The Doom-inspired UI bar along the bottom looked quite amusing, haven't really seen many games do something like that in recent years. Looks like it could be worth a shot, the action looks intense enough to keep me interested for sure.
While it's in Early Access, they're hoping to add a co-op mode along with new maps, new enemies, new levels and so on. The full release is currently scheduled for Q1 2019 although that may change depending on how much feedback they get during development.
- Story mode with three chapters
- More than 50 types of enemies to defeat
- Extreme boss battles
- Special arcade mode
- Ship upgrade-system
- Rhythmic soundtrack
Find it on Steam now. It's 30% off until November 16th.