Scenes

This 1st level could be divided in "scenes".
Each scene would be a platformer/puzzle to solve.

As in: Limbo

Intro: Biggy walks on the grass, then meets a first flower.
Biggy walks on it: it turns red (or black? = deathly shadow instead of a red trail)
Biggy is sad. (Lose all his happiness points)

Biggy goes further, meets other flowers and kills them all. (Always sad, visual + sound feedbacks)

1st:
Biggy meets a pike... stepping on it he hurts himself.
After that, he meets another flower... but is not big enough to hurt it. He is a little bit happier.

2nd:
Biggy is too big and cannot go any further: there is a tunnel but he cannot go in there.
Biggy has to bump on a "wall" (or anything) 3 times to make a kind of "stalactite" fall on him.
The stalactite hurts Biggy (and disappears): Biggy shrinks.