Steve, it sounds like you didn't watch Phil Lamat's INP file. He's clearing screens before he even eats all the objects. *AND* Iur Dhurin does eat every object on each screen, *AND* he's using the same version of mame (version 34).(posted 9509 days ago)Iur Dhurin also uses a stalling technique I saw in the arcades, by hitting a wall to stall the nibbler. Phil never seems to need to do that.
It's also possible that Nibbler is running at the wrong speed, I'm not certain.