The Shotgun looks like a hunter with a smaller barrel on it, and with two barrels on that, and another two smaller barrels on top of that.
The Shotgun upgrades from Hunter at level 45, and instead of firing two bullets, it fires six. One is slightly smaller than a destroyer's, one is the size of a sniper's, two are slightly larger than the auto tank's, and two are as large as the gunner's, and these are all fired one after another at a delay of about 0.1 seconds. The small bullets are stronger than their size would suggest, and their speed depends on the size. The large one travels a bit faster than the basic tank's, and the small ones travel faster than a ranger's. The Shotgun's reload is about 50% of the hunter's.