The game is a third-person shooter, placing players in the role of a new recruit to the Ghostbusters team known as "the Rookie" (also called "Rook", "Newbie", "Cadet", "New Guy", and similar names). Players control Rookie's movements as he explores the environments of each level, seeking out paranormal activities and ghosts, either alone or with up to all four of the other Ghostbusters. Players can switch to a first-person perspective by equipping the Rookie with the PKE Meter and goggles. In this mode, paranormal items are highlighted and the PKE Meter helps direct players to ghosts or haunted artifacts. Players can scan these elements to gain more information about them and receive a monetary reward. Weapons cannot be used in this mode.
In both the original and the remastered versions of the game, Terminal Reality's Infernal Engine allows for the Ghostbusters' Proton Stream to bend in real time, reacting as it did in the films.
In the third-person view, players can aim and fire a Proton Stream to weaken ghosts, allowing them to be captured in a ghost trap. Continuous use of the Proton Pack causes it to overheat, but it can be manually vented to cool it down and to keep it from shorting out and resetting. While the pack is overheated or being vented, players are momentarily unable to use the pack's weapons. Once a ghost is weak enough, players can switch to the Capture Stream to maneuver the ghost into a ghost trap. When a ghost is in the Capture Stream, players can also execute a "slam" attack to force it against a hard surface, further weakening the ghost and making it easier to trap. The Capture Stream can also be used to move objects in the environment.[11]
The single-player campaign is the same for the Xbox 360, Windows, and PlayStation 3 versions of the game. The Wii and PS2 versions have a significantly different campaign, but the stories are mostly identical. Over the course of the game, the Proton Pack can be upgraded to include additional firing modes other than the Proton Stream, such as the Shock Blast, Slime Blower (positively charged), and a Meson Collider, each with an alternate firing mode (a Boson Dart, Stasis Stream, Slime Tether and Overload Pulse). By capturing ghosts, as well as identifying cursed artifacts and new species of ghosts using the PKE Meter, players can earn in-game money to spend on upgrades to Proton Pack modes and ghost traps.[11] The game also tallies monetary destruction caused by the player, with Xbox 360 Achievements and PlayStation 3 Trophies awarded for either minimizing damage done, or for causing a high amount of damage.[14]
Many of the achievements' names come from quotes in the films, such as the "You Gotta Try This Pole" achievement. Other such achievements include "I Looked Into the Trap, Ray", "I Feel So Funky", and "You Never Studied".[15]
In place of a traditional heads-up display, the player's health and weapon status are represented as meters on the back of the Proton Pack. The player's health regenerates over time if they do not take further damage, but they can be knocked down by taking more damage. If there are other Ghostbusters still standing, they will attempt to reach the player and revive them. Similarly, the player can help revive fallen team members. If all of the active Ghostbusters fall, including the player, the player will have to restart at the last checkpoint.[11]
The Wii, PlayStation 2, and PSP versions differ slightly from the Xbox 360, PlayStation 3, and Windows versions. In addition to the cartoon-like graphics and the E10+ rating, the Wii version uses the Wii Remote for gameplay. Visual aspects of the interface are relocated, such as placing the Proton Pack's temperature meter as a HUD element instead of on the backpack. In the Wii, PlayStation 2, and PSP versions, the player "slams" a ghost by initiating a Simon Says-type game with the ghost, and the player is given the option to play as a man or woman.
