O1 was the source of my first successful software mod in 2008. No more timed game! I've been looking back over my working directory (which is named 'o1hack'.... still) and boy, did I just not know what the hell I was doing then (relatively). (Although, it does work.... just eliminates the minimum time requirements)
It's available on IPDB if anyone wants to check it out. I owned 2 O1 at the same time once (package deal) and a complete parts playfield (sorry, most of those parts are gone.... the spinning bumpers went first, of course). I wanted to put one of them in the downstairs bathroom (no one used it) so you can go into the narrow bathroom, shut the door, and have a surreal experience with the game. Sadly, the game was too wide to fit in there (and probably didn't clear the toilet, either).