Johnny Galecki first appears in "The Bowling Show" and introduces himself to the Conners as "Kevin Healy", which is how he is listed in the credits. In all subsequent episodes his character is called "David Healy."
In the scene where Rosanne gives herself a spare after she sits down the purple ball on the rack changes positions several times. First you see the serial number than the manufacturer logo than the Rhino logo and back.
While Dan's team is bowling, they are dressed in white tennis shoes. At the end of the game they offer colored bowling shoes to the losing team to drink beer from.