This game is masterfully good. I bought it several years ago and was blown away with how good it is. I'd like to cover a few key points that really make this game stand out from the rest.
-Original cast wrote the plot and voiced their characters! (Bill Murray sounds a little annoyed at returning.) The game is genuinely funny, intelligent, and spooky.
-Easily one of the most cinematic games ever created. The story intelligently bridges the first and second movies, as well as expands the Ghostbusters mythos and universe in intelligent directions.
-Revisit popular locations from the movies, without feeling like it's a gimmick! You have a reason for being there and doing what you're doing.
-There is almost no UI! Almost every function (health, overheating, "ammo", etc) is shown visibly on the character, via the Proton Pack, which actually manages to be easy-to-read and organic at the same time.
-Tobin's Spirit Guide is available for all the ghouls, ghosts, phantasms, class 5 full-formed repeaters, and spirit objects in the game, replete with their own back stories, lore, and rules. It allows enemies to be diverse and interesting, and fulfilling for lore hounds like myself.
-The game is fast-paced and fun, and switches the rules up often enough as to never feel stale.
The only cons I can think of for this game are that it's a bit linear, the upgrade system can be a bit of an annoyance from time to time, and the "teammate revive" mechanic can be a bit annoying, since the boys like to go down often on the tougher enemies. But none of these things deterred the experience for me and, at $10, this game is a STEAL! You HAVE to buy it. It's so worth it.