Smooth Sailing G10:
Complete any puzzle without using Undo.
This is a very simple achievement and you can do this as early as the first puzzle (Turtle) While you are solving the puzzle you can tap the sides of the screen and a little menu will pop up on one side which shows 4 symbols. The symbol that looks like a replay button is the undo button. Avoid touching this otherwise you will have to start over. I can recommend using the symbol below it however (light bulb symbol) since it points out every single match left on screen.