It's shaping up to be a really great game! Few ideas/observations...
*Possible Bug: I think in the new code they have text/sound alerting you "Ball X Locked" every time you lock a ball for Storage Facility Multiball. Seems like it does it only on the PREM/LE but not on the Pro. Perhaps this might be because there aren't any physical locks in the Pro? Nick from Arcade Heroes noted this when he videoed himself playing the new code on a Pro.
*I wish they'd have at least some brief reference to Vigo from Ghostbusters 2. Perhaps he could be the subject of some kind of mini wizard mode if... say, you collect all the Ghostbusters equipment from the left standup backs. No matter what you'd ought to get *something* special if you get them all.
*Really goofy idea, but if you end up winning the "Are You a God?" wizard mode (haven't seen it yet), they could pay homage to the original Ghostbusters NES game by displaying the infamous, misspelled "conglaturation !!!" end screen on the display.
*In general more callouts would be great, particularly when you start modes (currently, it seems like you get the same one every time at startup, which can get old after a while). Slimer also lacks a lot of callouts during his mode.
*During the Stay Puft mode, they could add more effects to Stay Puft. Specifically, they could have him light up and move about whenever he roars or stomps around New York City.