Spinball is inherently broken when it comes to score count. Nothing stops the player from getting into a controlled loop of, say, 25000 points each time (and unlike levels such as City Escape in SA2 which have similar infinite-point capabilities, Spinball isn't conducive to to any extra restrictions that would still be fair).
That, and total score would also need to add up the inter-level bonus stages (one of which is odd and gives out non-round bonuses of 464 points at three times over the course of play) plus the Multiball stage (which can be played up to four times in a single game).
For Sonic 2, Knuckles is identical to Sonic when it comes to special stages.
And Chaotix is still open to anyone. If you want a record, go try for one.