The Invaders
After overcoming years of denial, the invader has accepted the fact that he is not good at anything in life, and takes his place among the anonymous rank of invaders. He is the most common invader who moves directly towards the tower. If he decides that the route is too difficult or impassible, then he will start attacking traps or walls that get in his path.
Bent on destruction and angry at the world, the miner will actively attack any wall or trap it encounters until one of them dies. More powerful than the basic invader, he is adept at attacking. However, his speed is not as great as the basic invader.
After viewing some of Earth's high-quality 80's flicks, certain invaders have become enthralled in the retro counter-culture. Being as they don't have hair, they have made spiky mohawks out of metal. They move at a slightly slower speed than a basic invader. Whenever the cursor comes close to the spiker, he huddles down, spikes facing upwards, and waits; if the player tries to pick him up, the cursor pricks itself on a spike and is unable to pick it up.
Only the most mentally disturbed invaders go the kamikaze route. Running as swift as the wind, they charge forward and detonate themselves against the first trap or wall that gets in their way.
Invaders who are convicted of a felony are given the option to do 1,000 hours of community service or become a bomber. These invaders wander aimlessly with a timed explosive on them. When it detonates, a large blast shoots from the bomber and damages friend and foe alike.
The stacker is by far the most conscientious and lazy of the invaders. Instead of attacking head on and achieving glory for himself, which would require work, he stays behind and provides other invaders a stepping-stone on which they can scale walls with ease. With heavily reinforced box armor, this is the toughest of the invaders.
The driller is the type of invader who likes to think outside the box. When he encounters a trap or a wall, he tunnels under it and emerges past the player's defenses and much closer to the tower. The drill bit on his head is quite heavy which causes him to be much slower than the average invader.
Through extensive training, psychics have developed a method to move objects around through willpower alone. When they encounter a trap or wall, they alter its position with their mind powers to make the path to the tower as direct as possible. Some say that is the dark sensory depravation chambers that give them such a large eye.
The few who actually manage to survive a successful invasion instantly get promoted to a squad leader. These observant individuals are able to detect traps and coordinate other invaders' actions to get to the tower. Each squad leader acts as a drop zone that allows incoming invaders to drop directly onto his location.
Training for a ninja involves placing the recruit into the most horrible environment imaginable and seeing if they manage to survive for a few weeks; most do not survive. Those who do survive become swift and agile, able to scale traps and walls in a single bound.