For the game's incorporation of elements of adventure, arcade, shooter, and puzzle, see Harry Hughes (October 7, 2010). "ProtoGalaxy Review: A Well-Polished Arcade Shooter". PC MMGN. Archived from the original on November 21, 2010. Retrieved November 11, 2010.
For the maximum number of player characters and their requirement to defend Earth from aliens and restore human civilization, see Shirley Newhook (October 15, 2010). "Alien Attack Hits Province". The Telegram. Retrieved November 11, 2010.
For the game's incorporation of elements of adventure, arcade, shooter, and puzzle, see Harry Hughes (October 7, 2010). "ProtoGalaxy Review: A Well-Polished Arcade Shooter". PC MMGN. Archived from the original on November 21, 2010. Retrieved November 11, 2010.
For the maximum number of player characters and their requirement to defend Earth from aliens and restore human civilization, see Shirley Newhook (October 15, 2010). "Alien Attack Hits Province". The Telegram. Retrieved November 11, 2010.
For the game's incorporation of elements of adventure, arcade, shooter, and puzzle, see Harry Hughes (October 7, 2010). "ProtoGalaxy Review: A Well-Polished Arcade Shooter". PC MMGN. Archived from the original on November 21, 2010. Retrieved November 11, 2010.
For the maximum number of player characters and their requirement to defend Earth from aliens and restore human civilization, see Shirley Newhook (October 15, 2010). "Alien Attack Hits Province". The Telegram. Retrieved November 11, 2010.