Worms Armageddon is an artillery game/turn-based strategy game developed by Team17 and part of the Worms series. The player controls a team of up to eight worms in combat against opposing teams. Gameplay is turn-based, with each team moving in sequence (which is determined randomly) across two-dimensional terrain. During a single turn, a team can only move one of its worms (unless the Select Worm item is used). Worms can walk and jump, as well as (when the proper items are available) swing by rope, parachute, teleport, and bungee.

The objective of a traditional match is to defeat all opposing teams by killing their worms, although in the campaign some missions have other objectives (such as collecting a specific crate). Each worm begins the round with a specific amount of health (which is predefined by the chosen game options or by scripting in campaign levels). When hit with a weapon, the worm will lose health depending on the power of the weapon and the directness of the hit. A worm can be killed either by having its health reduced to zero or being knocked into the water around and below the level. (Wikipedia)

Unlockables

Items
Aqua Sheep - Earn a Gold Medal in Super Sheep Racing Training Mode.

Blue Sheep Mode - Earn a Gold medal in Super Sheep Training mode

Easy Sheep - Earn an Elite rank in Deathmatch Mode

Indestructible Earth - Beat Mission 25 and this should become unlockable

Invincibility - Earn a gold medal in Crazy Crates Training Mode.

Invisibility - Beat Mission 16 and this should become unlockable

Jetpack - Beat Mission 8 and this should become unlockable

Laser Sight - Beat Mission 4 and this should become unlockable

Power-Up: Grenade - Earn a Gold medal in Artillery Training mode

Power-Up: Long Bow - Earn a Gold medal in Euthanasia Training mode.

Power-Up: Shotgun - Earn a Gold medal in Rifle Range Training mode

Power-Up: Super Banana Bomb - Beat Mission 33 and this should become unlockable

Toggle Blood - Earn a Gold Medal in Basic Training mode.

Turbo Walking - Beat Mission 13 and this should become unlockable

Unlock Everything - Earn a Gold Medal and an Elite Rank in all of the Modes.

Here's one funny Worms video: