Worm level: Each defeated worm in multiplayer mode gives you exp. Furthermore, for every damage you'll get points, which are currency in game. With higher level your worm is being stronger and stronger! (more hp)
Personalization: For earned points you can personalize worm's look. You can choose mustaches, hats, hairs, glasses, lot of colors and many others like suit or husssars outfit.
Weapons: Higher level gives you access to new weapons like gun, sniper, laser, shotgun, hammer, flame. Weapons can be upgraded by points.
Trade: You can trade all your game items (weapons, addons, points) with friends. All you need is (love) just put phones together! (nfc).
In case of no internet connection you can play in single player mode