Dr. Egon Spengler's mini has a very stern look on his face, hiding behind his rather prominent glasses. Much like the character brought to life by Harold Ramis. The name tag also has SPENGLER written quite legibly across it in red. On his right arm the Ghostbusters Logo is proudly displayed, bright and very noticeable.
Egon comes with a Proton Pack which is not detachable. The Neutrona Wand comes off the pack, and is attached by a small string of plastic. The Wand has an added handle to make it easier for the minimates to hold it.
The Pack itself is highly detailed in its design, with minimal paint apps, but said paint apps are put in just the right spots. The 4 lights of the cyclotron for example are a bright red, while some spots are touched in a shiny silver.
As expected, Egon also comes with a mini PKE Meter, the arms and screen have a shiny silver paint applied. The PKE can attach to Egon's belt much like the Neutrona Wand can attach to the Proton Pack.

Also, along the belt the belt gizmo sits.

Next up is Dr. Peter Venkman, made famous by none-other than Bill Murray. Peter's minimate has Venkman's signature receding hairline and his face, while having no real expression, still somehow has his cocky attitude about it.
Like Egon, Peter's nametag has VENKMAN across it in red; the detailing of the straps and belt are all there with the belt gizmo in place. However, in place of Egon's PKE Meter, Peter has a lil radio, so he can call Ray if he finds a certain ugly little spud.
Peter's Proton Pack and Neutrona Wand have all the same details in mold and paint as Egon's and his arm patch is just as bright and noticable.

Louis Tully aka Vince Clortho: the KeyMaster is represented in minimate format from after the destruction of Gozer at the end of the movie. Covered in soot and burns, Louis looks more than a lil disheveled. Out of all the minis I've seen, it looks to me like this one comes closest to their movie counterpart in the face (that being the always funny Rick Moranis).

Now Louis is unique as he comes with all the spare parts necessary to turn him into a Terror Dog. Now most of these come off easily, although I found the tail piece to be rather difficult and, admittedly, I was afraid of snapping something when doing so and as such have not reassembled the pieces. (Luckily, another Terror Dog is released in one of the Toys-r-Us exclusives).

Last on the list is Miss Dana Barret when she was possessed by Zuul: the GateKeeper. Now Dana doesn't have any accessories to speak of, but her dress matches her appearance in the movie almost to a tee. The dress shines and glitters, the only slip-up I noticed is the slight missing of paint app along the bust line (looks like it went along the wrong crease line).
Now Dana's face has no real distinguishing features to showcase it as being a toy based on Sigourney Weaver, her hair on the other hand really shows off the 80's vibe and is crafted quite well.
My only real complaint is the dress's slit doesn't move so you can't have her perched in that sexy pose with her bare leg bent at the knee. But if that's my only complaint about this set (and it is) then we've definatly got a good start to what will hopefully be a long & fruitful series of Ghostbusters toys to come.