It's my favorite tactical game. Actually it was my first PC game purchase back in 2013. $5 is an insane deal, the PC game is $20, and the amount of content is just huge.
6 themed campaigns, with more to come. 80 single missions. A scenario editor for endless challenges. Skill trees, squad classes, and customizable loadouts. A simple control scheme that always felt like it was better suited for mobile.
And way more tactical depth than Frozen Synapse and Breach and Clear. FS provides more complexity, but Door Kickers provides more "real" tactics. You can split your team between a stealth and assault force, stack up on doors, use flash bangs or breaching charges, set up go codes and simultaneous breaches, use non-lethal tactics. You're rescuing hostages, performing drug raids, and taking down terrorists and cartel gangs.
The game is fantastic