I watched this without knowing anything about it and found it to be well made and fun with a good cast and great practical effects.
The only thing I didn't like was the protagonist, which is a shame. I understand he's supposed to be awkward but right from the bat he's extremely annoying and very unlikeable, his acting is too much over the top, and the character doesn't improve or develop in any way through the story.
The rest of the cast is not so bad, but feel like they're just in there as a filler.
What really made me watch and enjoy the whole film was Jeffrey Combs and Olivia Taylor Dudley. They are the high points and it's worth watching for the two of them.
This film had a lot more potential, It could have been rated higher if the main protagonist was more likeable (not such a loser), or he developed and grew in some positive way through the story. Or if the actor played it normal/straight, and not like a caricature.
The humor is good for a chuckle, but it's sometimes too childish. If it had been straight or dry humor like in the original Ghostbusters, it would have been amazing.