1) Attachments – just like with modular armor, you can equip the in-game tank with various modules and weaponry: laser turrets, batteries, a force field, and even a drone station!
2) Three weapon types: a primary projectile-firing gun, a standard machine gun, and a flamethrower (using its own fuel). You can switch between weapons using the 'C' key. Plus, it has a spacious trunk.
3) Cannon shells are crafted from explosives, plastic, and steel beams. This means oil processing must already be unlocked.
If you also bring repair kits and drones along, the tank becomes virtually indestructible, and clearing out bug bases becomes quite satisfying.
Tank + grenades = imbalance
You don't even have to craft shells for the weapon.