Sorry, man. This is a mess with lots of problems.
Let's start with the menu, the title font is terrible, the way it just moves in and out is annoying as hell. The instructions page is a jumbled mess with completely off the margin paragraphs and the next button in itself was glitchy because it took me a couple of seconds to get it to work.
So now comes the game proper, most of the time, a single jump can send you falling through the floor in nothingness, which is what happened to me in my first five second of the game. Not exactly a great first impression. So I have to refresh the browser to try again, no flash game in any way, shape or form should require the player to do this, more or less not having a stable floor to walk on. So I finally last past the first couple of seconds to be met with some really bland gameplay, it is just empty space with a Slimer or two to zap. And dear God, chief, add a run button or make him walk faster, his speed is too slow. Also, even though you can jump on top of stuff, you get stuck between things half of the time.
So, after frantically typing the Z button to get out of a glitched building, I finally get to Egon. I turned back, jumped over a vending machine, and once again, clipped through the floor. This is simply inexcusable, man. If a game has this many glitches, do not release it.
Here is some tips to make this less of a terrible trainwreck. Replace the title, it doesn't look cool at all and it just looks super cheap. Redo the instruction screen entirely and make sure that your letters do not run over each other and that the next button can be clicked with ease. Most importantly, fix the glitches, the falling through the floor bug alone merits an instant 0, if you don't know how, reading a few tutorials wouldn't hurt. Turning something as bad as this into something playable is going to take a load of work but if you work hard enough you may do just that. If not then flash games just isn't your thing chief.
Sorry for the massive wall of text and best of luck.