Go thru the game on Professional (or just Experienced if you really don't think you can do this) and try to trap as many ghosts as you can WITHOUT using the slam technique. None, no slamming of the ghost at all. To me, anything you can do to make trapping a ghost take longer just makes it more fun in my opinion. The only level that really gave me a hard time in trying to catch ghosts without using Slams was the level in the museum with the Possessors when Ilyssa gets taken to the top of the Gozer obelisk. Its kinda like going up against Vigo on that part of the level from GB 2. Made me want to do it this way even more after I thought of that. Seems like everyone is always looking for the shortcut and here I am trying to find the hardest way to go down the road. But my way, its more like im really there instead of playin the game.
Another thing is, when you go to trap Slimer in the Alhambra ballroom, i know we all have torn that room to pieces, but has anyone ever been able to zap and trap Slimer without messing up the room at all? Ive gotten very close to having no burn marks on the walls, no destroyed tables or tablecloths, no lights blown out, but i always end up destroying something or leaving burn marks. Anybody ever managed a ‘clean’ capture?
Give it a shot, see if you can do it.
Oh and on a easter egg note, did anyone notice when you do the Hindenberg part of streets of new york, when the first fat lady ghost appears, there's a billboard to the upper right of her that says ..actually I don't remember what the phrasing is exactly but its something along the lines of Loud Enough? I thought that was a nice touch.