I'm really sorry to have to say this...
... but I'm just really not seeing a positive, even taking into account that this is a beta version. The ground work is there, but the overall execution is terrible, and even in a test release you sure don't want your characters falling into the abyss of a noclip zone. Your music is repetitive and gets annoying fast (hey, I'm a fan, but that song still gets grating after awhile)- I'd at least mix in some of Elmer Bernstein's original score.
But, I think the biggest mistake here is just the idea of making a Ghostbusters based game. Because of the subject matter alone people are already going to have a fairly high expectation, and it's going to be impossible to meet it. Why not improve your skill and try something that's entirely your own? I'd honest much rather play that. If want to play a Ghostbusters game, I'll play the new one that came out earlier this year. If I want a side scroller, then I'll fire up the Sega emulator and play the old 16 bit version that you took your sprites from.
Please don't take this as a put down. This is still more than I'm capable of, and I applaud your effort. I just think you're cheating yourself creatively and I'd doubt that your making many friends by doing so.
Fix the bugs, remodel the game, and make your own- that alone will get you a considerably higher rating in my book.