The game basically follows the same plot as Aliens: Colonial Marines, with some alterations.
- Patrick "Stainless" Steele
- John "Duke" Cameron
- - One of four starter playable characters. Typical "Natural born leader" stereotype.
- Buddy "Brando" Whistler
- - One of four starter playable characters. Typical "Rookie and inexperience" stereotype.
- Samantha "Homewrecker" Johnston
- - One of four starter playable characters. Typical "Hot-head woman" stereotype.
- Brock "Bear" Paulson
- - One of four starter playable characters. Typical "Gentle Giant" stereotype.
- Amber "Buster" Fischer
- - A teenage girl who become colonial marines to stay away from her over-protective brothers.
- John "Booker" Lasso
- Jeff "Lucky" Palms
- - A marine who was well known from his good luck. He always survives from many war and accident that nobody survives.
- Jay "Gristle" Henick
- Deepak "Cowboy" Singh
- Hank "Husker" Thompson
- - A marine who came from former wealthy family. Possibly the most positive-thinking marines in this game.
- Angel "Cuchillos" Sinise
- - A con man and former gang member who choose to be marine to not getting jail sentence.
- Zoe "Cutter" Kennedy
- - Goth and Emo looking marine who have troubled on her past life.
- Dave "BBQ" Williams
- Frank "Bonesaw" Heston
- - A gun fanatic marines who gets "Bonesaw" nickname from his past war when he used his smartgun to blow off a marines leg (Possibly Jeremy Cruz from Aliens: Colonial Marines) after an APC was flipped over due a magmine.
- Mei-Lin "Beta" Chau
- - A hacker and computer fanatic who became marines for her hacking specialist. Often speak computer words on her conversation.
- - A marine who was rumoured to be synthetic.
- Mike "Five-Pack" Coleman
- - A marine who suffered from Posttraumatic stress disorder.
- Jimmy "Chiever" Kim
- - Last recruitable team member. Join an army to follow and his father footsteps and tried to be success than him.
- Jasper "Iron Sights" Watson
- - The oldest member of playable characters
- Jockey born Xenomorph
- Gorilla Alien
- Gorilla Alien Praetorian
- Unknown boss (possibly a Xenomorph Empress or a young Queen Mother)
- This game was supposed to be Aliens: Colonial Marines for the nintendo DS but was cancelled but was re-released with the name Aliens: Infestation with a few minor alterations.
Aliens: Infestation was featured on the Feb. 25th episode of the video game documentary series "All Your History Are Belong To Us" on the Machinima YouTube network.