A direly needed step, bug fixing. Usually if I encounter a bug and for whatever reason can't fix it right away I'll note it down (it's just too easy to forget). This step fixes:
Spawn count bug fixed (a stage would not be detected as done)
Major slowdown when playing with Sam (bad bad bug)
Car sprite error in story page (failure to properly reset)
Left over char N in mode choice (tiny oversight)
Other player spawing although no lives left (failure of proper two player testing)
Most of these bugs are trivial and so it's not much use going into details here.
It can't be stressed enough. Often I catch myself encountering a bug while playing and just thinking "I'll fix that later". Well, in a lot of cases I forget. If you write a game, test play it, encounter a bug: Break the game, fix the bug. It'll move you forward faster.