FlowLink
Some puzzles look easy until you try them. FlowLink on igrasu.ru is our take on the classic Numberlink: no fluff, just colored dots, an empty board, and your brain.
The rules in two sentences
Connect two dots of the same color with one continuous line. Every pair must be linked and every cell must be filled. That's it. The difficulty comes from the fact that the board has exactly as much room as needed — there are no spare moves.
Why it hooks you
Unlike sudoku, there are no numbers and no brute force. There is visual intuition: you see where the blue flow got stuck and realize the red one has to run along the edge. When the last cell fills and the board lights up in every color, it is a small but honest triumph.
Where to start
Begin with small boards — the whole structure of the puzzle is visible there. Don't be afraid to hit 'Reset': redrawing a line is faster than planning three moves ahead. The 'How to play' tab nearby explains the controls in Russian and English.