Click to place the happy pill. Click again to fire it. Try to bounce off of everyone who's sad -- but not too many times.

Mr. Sad needs one hit to make him smile. Four is fatal though.
Bi-polar Bear switches between happy and sad each time it's hit.
The Hippy can take 9 hits before going down.
Flush Rimbowl eats pills like po'corn. Stay away!
The Tunnel transports the pill, to like another dimension (ok, just to another spot on the board.)