I have checked the game and it doesn't appear to have a menu. To start a new game, you will have to delete the previous progress. Luckily, this can be done using the phone without the need to install other tools. Go to Settings > Applications > All > Alchemy Evolution 3D. Tap on Clear Cache and Clear Data and then start the game and your progress will reset to 0, then you can start over.
This is a common method to wipe the progress for an application.