A perfect level is when you finish each flow before starting the next one. There are quite a few ways that you can manipulate this to make sure you can get a perfect level without having to completely restart the level, which can be very important for improving your time.

1. How moves work: After making a move, the game checks if it's the exact same board state as it was before. This means that if you start drawing a flow, but then realize that you don't know it's entire path, just keep your finger on the flow, and return it back to the original dot you took it from. Because the board state is the exact same, the move counter does not increase.

2. The Undo Button. The game keeps track of 2 board states - the current one, and the previous one. The undo button returns it to the previous one, including the move count, or if any flows were erased by new ones you drew. This means that if you accidentally cover over other flows, just release your finger and press the undo - no need to restart the entire puzzle, as that can be especially costly on larger levels like 8x8 and 9x9. In addition, if you ruined a flow, but already started moving the next one, just make sure you drag it back to where that flow started (like described in the 1st point), and then you can press the undo button.

Note: To progress to the next level quickly, animations has to be turned to all, and you just click on the level anywhere. Often, you will accidentally try to move onto the next level without the flow being completed. This absolutely sucks when it happens. To make sure you can actually undo that move and don't have to redo the entire level, there are 2 options, depending on what you prefer. You can tap the second time on the exact same place you finished your last flow, or you can try to tap on the surrounding black area that doesn't have flows on it, so that there is no chance of messing up the puzzle.

Something cool: The game only checks every other frame or so if the level is complete, so you can actually finish the last flow, and then proceed to tap on the screen to move onto the next level, and mess up a flow. If you just press the undo button, the game will register the completion and move on to the next level.