Thank you for playing! The fill count not going down is actually on purpose. This is not a game with a countdown, this is a game where you count down! so you have to count yourself and see how well you did when you squish the squishy button :D
The way you win is by filling the mattress perfectly, preferably with one of the later birds you unlock in the game.
Either way, this is a fair critique and should have been more clear.