For those who enjoy their classic shoot 'em up experiences, Demonizer on itch is pretty retro looking and the action is rather intense.
Currently in-development so it's an Early Access title, Demonizer is estimated to be completed sometime midway through this year. Take a look at some quick gameplay of the demo version running on Ubuntu:
As you can see, the action is absolutely nuts. Given the small gameplay area, the amount of enemies and projectiles flying around does make it quite the challenge. Quite keen to see this one finished, the multiple fire modes with the heart collecting mechanic to gain friends is quite interesting.
More about the game from the developer:
The outcast princess turned succubus must stop cruel Kingdom troops from slaughtering friendly monstergirls in this 90s-arcade-style vertical shooting and man-catching challenge.
- Blow up war machines and break the soldiers' will with hot demonic seduction blasts
- Collect men to nourish you with spiritual energy; transform women to grow your succubus squadron
- Charge up a massive spiritual/demonic explosion to flush out soldiers in hiding
You can pick up a copy for $5 (or more) with the price going up as it's further developed. Take a look at it over on itch.io if it looks like your thing.