Wave based shoot em up where you play as a mercenary manning a mounted gun fighting off the aliens assaulting his position. Good variety of equipment including different ammo and shot types, grenades, melee weapons, thrown weapons, and passive bonuses. Killing enemies grants you points you can spend on buying weapons, ammo, and skills and upgrades for them. Good variety of enemies that can either attack you in different ways or support each other with shields or buffs. Killing enough enemies will grant you a choice of temporary bonuses. Five areas with a boss at the end of each one, challenge modes, new game plus, good music, and nice art style.

Screenshots: https://twitter.com/Legolas_Katarn/status/1295199167929675776