Level 1
Tier Apprentice
Toggles 0
Hints 3
Stars 0
How to Play Rullo
1. Read the targets
Every row has a target on the right. Every column has a target at the bottom. The number is the sum of the cyan cells in that line.
2. Toggle cells
Tap a cell to switch it between ON and OFF. Cyan cells are added to the running sums. Dim cells contribute 0.
3. Lock the sums
When a row's running sum equals its target it glows green. When a column matches, that column glows green. Lock every line and you win.
4. Use hints
Stuck on a row? Tap Use Hint to highlight one cell of the canonical solution. The unique answer is always one toggle away.
Tips & Strategy
- Start with the most constrained row or column — the one whose target is closest to a sum-of-all-cells in that line.
- If a row's target is very small, look for a single small cell to leave ON. If it is the full sum, leave everything ON.
- The hint reveals one cell of the unique solution. After using one, the rest of the grid is fully determined for skilled solvers.
- Undo lets you roll back the last few toggles without resetting the whole level — perfect for trial-and-error.
Related Games
If you enjoy Rullo, try Kakuro, Kakurasu, Pulse Path, and PathPix for more constraint-driven brain puzzles.