I just beat Ghostbusters, and here's my oppinion.
Holy shit that was actually pretty decent.
The gameplay was engaging enough, but it didn't vary much, so the game flirted with over-repetitiveness a lot. The game wasn't exceptionately long, but not too short either. The story was pretty good, which isn't suprising since it's derived from a script that was going to be Ghostbusters 3 and was written by Dan Akroyd and Harold Ramis.
Speaking of them, all of the original cast are here, reprising their roles from the movies. The voice acting here is awfully lopsided. Dan Akroyd returns as Ray Stantz, Harold Ramis as Egon Spengler, Bill Murray as Peter Venkman, Ernie Hudson as Winston Zeddemore, and Annie Potts as Janine Melnitz. They all give pretty good performances, except for Bill Murray, who usually seemed completely uninterested, delivering his comedic lines with the same comedic flair that pudding skin gives. His character was also hardly in the game at all, which left the game feeling like it was missing something at points, but it doesn't suffer too much from that.
My biggest gripes with this game are Murray's voice acting and the fact that there's only 4 weapon types, and while each has two firing functions, I kept wishing there was more variety. Luckily, the weapons are all visually and tactily interesting. The proton beam is your default weapon, and the only one you have at the game's start. The normal firing mode is a stream that can burn obstacles, crubmle stone structures, and or course, weaken ghosts so you can capture them, and here's where the game really shines.
Catching ghosts is really damn fun at first, gets a bit old, and then you get the Slam Dunk Trap upgrade, and suddenly it becomes as fun as I always hoped the game would be. The process of catching a ghost is broken down into three steps. First you hit them several times with your weapons until their health bar turns red, then you throw out a trap and use your captrue stream, which is automatically used if you attempt to use your proton stream on a ghost with low health, to slam them around. Slamming is accomplished by tilting the stick in a direction and hitting the slam button, the left trigger on the 360, and your character jerks the proton pack's wand in one direction to send the ghost flying against the ground in with asatisfying THUNK or SPLAT. Finally, you pull the ghost towards the ghost trap you sent out, and when they get over the trap, it opens to start pulling them in, and you have to provide resistance as they try to escape the pull of the trap. Finally, they are sucked into the trap with an even mroe satisfying sound. This whole process is made more fun with the Slam Dunk Trap upgrade, which allows you to simply slam the ghost into the trap, and that's one of the best feelings in the world: successfully slam dunking a ghost into a small ghost trap. The player can use the caprture stream on certain small objects also, in a manner not unlike Half-Life 2's gravity gun. The secondary fire of the Proton stream is called a "Boson dart", which is basically a large blast that causes enemies lots of damage.
The other weapons you have include the "Dark matter generator", which has a primary fire siilar to a shotgun blast and a secondary fire that sends out a beam that freezes ghosts as if encased in ice.
Another weapon is the slime gun, which has a self-explanatory primary fire and a secondary fire called the slime tether, which you can use in a Portal-like sequence of firing at two different spots to create a string of slime between objects and other objects (or walls, cielings, the floor, etc) and causes the objects to be pulled steadily together. This is used in a few easy-to-solve physics puzzles that remind me of playing around in G-Mod. I'll just say that this is an under-utilized feature that I wish the game had explored further.
The final weapon seemed like an afterthought. It has a primary fire that behaves like a slightly more accurate but weaker boson dart, and a useless machine gun-like secondary fire that really should have been the primary fire. You don't get this final weapon untill near the end of the game, and I hardly ever used it once I did get it, even when I replayed the game on professional difficulty.
This is a suprisingly playable movie game that, although it's not spectacular, is still one of the exceptions to the rule that games based on movies must suck. It's worth at least a rent. I never played the multiplayer, so I can't give you an oppinion on that, which means I can't telly ou accurately if it gives the game the required replay value needed to justify a purchase.