Horizon Vanguard really needs some love. No one plays it at all, and it's really fun. It's not going to win any graphical awards, but it's a great & difficult fast paced game in the style of 90's arcade shooters.

https://store.steampowered.com/app/598740/HORIZON_VANGUARD/

It's a little overpriced initially since you have to keep unlocking more maps, but wait for a sale if you prefer.