All collectibles should be defined in an identical way as powerups, so coins and gems should too as they aren't.
This involves adding "add score" and "add coin" effects.
To discuss:
How coin and gem count tracking should be done in that case (level variables, perhaps? is it worth to add unnecessary complexity to both code and game creating process?)
Work out other possible life systems first (no lives at all, lives granted every X points etc.)
All collectibles should be defined in an identical way as powerups, so coins and gems should too as they aren't. This involves adding "add score" and "add coin" effects.
To discuss: