Taking tactical SWAT-style planning to a new level this lets you draw on the actual maps you'll be playing as you work out tactics. Obviously your tightly coordinated plans will all collapse the second anyone does anything but that's half the fun.
During the planning phase you and the enemy team will be able to gather equipment and decide on tactics, drawing arrows and circles over the map which is actually the level itself. When you start all your squiggles will be painting over the floor and walls like a child's scrawl.
It just looks like so much fun to plan/play/really, really mess up.
According to the developer Giant Enemy Crab this is 'alpha as fuck', the box figures and plain assets all placeholder as the basic gameplay is tested. A post on the official website says the finished game will "have an art style resembling Hotline Miami and the latest Dredd movie with a lot of bright colours".
There's a playable alpha on the way but currently it's only for North America because of servers. Hopefully that'll be fixed soon.