(Very) Hard AND nice puzzles
The following list contains portal puzzles that have been rated as nice or very nice and that are difficult. These puzzles are recommended for experts - and allow some time to solve.
| Description | solved | Rating | |
|---|---|---|---|
 | Dutch Flat Mates: Y-Sums by Crusader175 (on 18. June 2025, 08:36) | 57 |  94 % |
| Colorful symmetry by Adrian71 (on 29. August 2025, 18:01) | 17 | 94 % |
| Volley Fire (0-9 Challenge) by The Bard (on 15. January 2026, 20:43) | 47 | 95 % |
| Einstein Sudoku (collaboration with Synergenesis) by mbumbee (on 5. March 2026, 21:31) | 82 | 94 % |
| Keeping Tabs by MSDOS (on 6. March 2026, 00:56) | 25 | 93 % |
| Cobblestones by Sotehr (on 4. April 2026, 10:17) | 64 | 98 % |
| The Butterfly Effect - Region Sum Lines Sudoku by Mr.Menace (on 28. February 2022, 20:11) | 106 | 97 % |
| Freeze by Jobo (on 17. December 2024, 07:44) | 102 | 98 % |
| This is Sparta! by NicoD (on 19. April 2026, 05:30) | 81 | 96 % |
| Sudoku Variants Series (415) - Parity Poopers by Richard (on 14. March 2025, 12:00) | 71 | 96 % |
| Benebelte Nachbarschaft (FOW) by Myxo (on 19. August 2023, 05:25) | 393 | 96 % |
| Fraction Party by sujoyku (on 12. September 2023, 19:46) | 66 | 97 % |
| Battlefield Sudoku by Realshaggy (on 31. May 2020, 13:08) | 61 | 96 % |
| Sudoku Variants Series (328) - Sudoku Heatmap by Richard (on 7. July 2021, 00:00) | 61 | 94 % |
| Subway Lines (Chaos Sandwich Sudoku) by Agent (on 15. April 2022, 09:00) | 55 | 98 % |
| Archery Zone by Ridhwan (on 3. June 2023, 18:16) | 65 | 97 % |
| Coincidence by fuxia (on 1. June 2024, 14:37) | 54 | 90 % |
| seven swans a-swimmin' by aqjhs (on 18. December 2024, 03:45) | 120 | 97 % |
| Jungle Gym by PotatoHead21 (on 28. September 2023, 01:08) | 105 | 96 % |
| Krypto-Kongruenz-Rundweg (2) by ibag (on 6. September 2009, 18:31) | 46 | 94 % |
