Tarnation

Variously coloured gobbets of tar are seeking to pollute your water supply with their dark, sticky evils. All that stands between you and them, is a small patch of seeds. These are no ordinary seeds: these seeds grow to be different coloured flowers based on how you group them with your mouse; these seeds are capable of flying through the air and homing in on similarly coloured tars; and these seeds can then neutralise that tar and in doing so quell the imminent disaster.

There is a skill to knowing how many flowers it will take to destroy a tar. It's not a skill one needs in everyday life, but in Tarnation it's vital. The use of the draggy, groupy file-moving feature in this way is nice to see (and perhaps a first?) and lends itself well to a style-matching game. This game ain't too tough, but you'll need to learn what it wants if you're to succeed.

Drag from top-left to bottom-right to make red flowers, from top-right to bottom-left to make blue flowers and from bottom-left to top-right to make yellow flowers.

See if you can destroy the tars as close to the river as possible, then there is more chance that the flowers can move on to battle a tar that is following on, thus getting the best mileage out of them.