"A reckless band of enemy hogs have been mercilessly wreaking havoc on the small islands that make up part of Hogshead. Take your boys along and administer a sound thrashing to demonstrate the error of their ways!"
-Major I. P. Grimly
The terrain is mostly bracken (grassy), being known for the labyrinth of water ways, making up several islands. The players pigs are located on two of the islands (3 and 2 on each), enemies are mostly located on an island with two shelters, except for sapper, who is on his own island next to player's island with two pigs, and scout, who is in corner of the map and often remains without much of player's attention and often is killed as last. The area is also made from several normal, but also several broken bridges, from which pigs can jump, but they can't get back on the previous island they came from. Some islands are not connected by bridges, there is no bridge between two player's islands and there are no bridges leading to the main enemy island. There is also some land on the edges, but due to slopes, it is difficult to move through it, so best way is to be on the islands. But due to missing or broken bridges, swimming is sometimes required to get on some islands.
In this level, there are three shelters, all of them on islands. Two shelters are located on main enemy island, one of them is on the player's island with three pigs.
There are no pick-ups located in this level directly, but there are three Useful Provisions boxes, all containing 20 UP. After some time, a box containing 50 UP lands in a crater in the corner. If player manages to kill the scout during the game, there lands a pick-up containing one Airburst on place, where scout used to be at the start of the game.
There are five enemies in this level- two of them are gunners with health of 75, one is orderly with health of 60, one is sapper with health of 80 and one is scout with health of 75. In the Hard Mode, there are two bombardiers, one medic, one engineer and one sniper.
- Island Invasion is the only level to include a sapper in the single player campaign
- Island Invasion is the first level to not have a single grunt
- Island Invasion is the only level to include all of the ranking classes
- Island Invasion was ranked as the best Hogs of War single player mission by the Hogs of War community