No back story, nothing extravagent, just get the coloured marbles to the correct homes in the allowed time.
At the start of each level, you will be told your quota and how long you have.
Your job is to get the marble from the launchers to the homes. There may be more than one launcher and more than one home.
It's your job to make sure the pathways are correct for each of the marbles.
In order to guide the marbles home, you need to influence their direction. This is done by activating the rotators to change the pathway. Once a marble starts on it's path, it won't stop until you change it's direction, it hits a dead end, or makes it to a house.
If the marble colour you need is not in play, you can direct the marble through a colour changer, and it will change to the next colour in the sequence. The sequence? It's not that difficult to see.
Grey Marbles. These can be used in any home and they count, but you will only get half the points though. If they pass through a colour changer, they will revert to a colour. Which one? Who knows? They also have an extra feature, but see the black marble note for this.
Black Marbles. This will destroy your house instantly. If you lose all of your houses, then it's game over. Some levels require you to have all you homes intact by the end or you will fail. Fear not, as getting a grey marble home will restore all homes back to normal.
Smart Bombs - If it all gets too much, you can use a smart bomb to clear all the marbles of the screen instantly.
You can't use these all the time though, you need currency. You gain these by collecting the stars along the way. You get a new bomb every 5 stars (although if replaying a level, only new stars count).
These count in a number of ways. Collect these with any marble (except black), and you'll get a bonus at the end.
Collecting these will also count towards getting extra smart bombs, although using these comes at a price though.