The current normal mode speedrun goes to credits after level 15: https://www.speedrun.com/zooogba/run/ywk34g2y

The second place normal speedrun continues to level 16: https://www.speedrun.com/zooogba/run/yd624q0z

This video completes level 15 at 17:01, then after the "clear" screen (which seems to be every 5 levels) continues all the way to level 20 before getting the credits: https://archive.org/details/game-boy-advance-longplay-zooo-action-puzzle-game-eu

Are you saying that on top of the per-level quota of each level there's a hidden "total of each animal" threshold that must be reached to get the credits?

Hello,

Can anyone tell me why normal mode ends at level 15 in some cases, and level 20 in others? I understand that the normal speedrun rules are for the end of level 15, but am curious why the mode sometimes continues past that.

Thanks!