Budbrain's Marbles

Click one tube, then another. The top marble flies over in an arc and lands. It may only go onto an empty tube or onto one of its own colour. Get every tube down to a single colour and the puzzle is yours. The first ones are over in three moves. Later there are fifteen colours in the glass at once, and you sit and think for a while. A hundred and five puzzles in twenty stages, and every one of them was worked through beforehand: there are no dead ends. Took a wrong turn? Take the move back, or start the puzzle over. The game remembers where you stopped, and every puzzle you solve stays on the achievements wall with the way you left it.