Where do I start. Could have been way better but equally not that bad either. Don't know what they were trying to do with the humour in the movie but it's like they tried to force it then thought better of it and stopped anything that could actually be funny. I liked that they tried to make it a bit darker and jumper, which I thought they did quite well. One thing I wasn't looking forward to was the supposed love side plot between the younger Spengler and a female ghost but in the end it wasn't over the top ramming it down your neck and might be construed as a friendship rather the a forced dei push. The fire master character for me was a waste, it brought nothing, no humour or serious threat to the big bad guy. And the legacy characters where also kind of wasted, venkman for instance was a shadow of bill Murray's original character which was sad to see. I think going forward better direction, better and writing could help this cast make decent movies. The old guys need to be allowed be themselves (venkmann) or not be included at all.
Overall it wasn't great but it wasn't absolutely terrible either. If you're an avid fan you'll find something you like, if you are looking for well written, strong storytelling with really good humour you'll be disappointed.