I should now reveal what I've been working on. It is a hack that gives a serious facial uplift to the original game. Without further ado, here are some images (nothing final):
click to enlarge (title screen credits go to Macbee)

It is mostly original graphics, but slimer and the heroes are adapted from the "new ghostbusters 2" game from HAL lab.
The title screen says "os caça-fantasmas" but that will be on the brazilian portuguese version only. As with the super pitfall hack, I will release this in both US-EN and PT-BR.
As usual Macbee has been looking closely at the progress and making nice suggestions (his idea to use the new gb 2 graphics). Also, he did the graphics for the new title screen and made it pre-stretched to compensate for the nes aspect ratio on the tv (things I never even noticed, but cannot be unseen!).
I didn't pick this game because of this, but it is another badly ported/adapted david crane game.
I don't think the game design can be saved on this one, so I just want to work on graphics mostly. I was thinking a few tweeks here and there, but nothing complicated. Oh, and I've fixed the stairs controls. Now you just press LEFT or RIGHT to move LEFT or RIGHT. Like a videogame!
Also, on the boss scene I've made it so you can move freely and the screen won't switch (that was super annoying on the original game). Now you press B if you want to go to the staypuft marshmellow man screen (press B again to return). Also! I've made it so you always shoot up.
I also noticed these errors with the original game:

This one is weird, they made the graphics but inserted the wrong numbers for the sprites. Original game on the left, restored graphics on the right:

This is all I have so far. To do are the other 3 variations of the background on the ghost hunting scene, the staircase scene, the final scene (both screens), the shop and a few details, like the gas station, the GBHQ, running out of fuel, etc.