As a twin-stick shooter, this is uninteresting. There are minor upgrades in weapons and abilities after each boss battle. Otherwise, dodge bullets and shoot an infinate supply of enemies.
As a topdown GTA clone, it's only charm is the doodle graphics style. Otherwise, it's just killing people trying to kill you with cars or guns. In my first 3 "missions" the only goal is to go into a bank (not sure why it's a bank other than the name on the roof) and kill someone with a better gun than I have.
Maybe there's more? I don't think so and I'm not interested enough to find out.