(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 | |
|---|---|---|---|
 | Spiral Fillodoku (Spiral Galaxy, Fillomino, Killer sudoku hybrid) by AnalyticalNinja (on 29. March 2023, 21:25) | 57 |  98 % |
| Exums by Xenonetix (on 27. May 2022, 22:22) | 44 | 99 % |
| {Arrows,Collection} by Prof.Dori (on 13. June 2023, 14:26) | 47 | 97 % |
| Parity Killer by SudokuExplorer (on 7. July 2021, 03:36) | 40 | 94 % |
| el veloz murciélago hindú by aqjhs (on 6. November 2024, 18:12) | 42 | 91 % |
| Wichtel 2013 (10): Doppelschlangen-Höhle mit Doppellöwen by wichtel (on 30. May 2014, 10:32) | 27 | 99 % |
| Modular Snakes by Prof.Dori (on 27. October 2023, 09:20) | 34 | 100 % |
| Japanische Summen PQR by tuace (on 4. November 2016, 15:30) | 48 | 98 % |
| Krypto-Kakuro-Koralle für pin7guin by ibag (on 6. September 2013, 00:00) | 60 | 99 % |
| Palindrome Madness by SirWoezel (on 2. June 2020, 18:26) | 23 | 93 % |
| Haisudoku Thermoline (Thermo Sudoku+Haisu hybrid) by AnalyticalNinja (on 15. November 2022, 03:02) | 21 | 100 % |
| Three-Line Riddle by JeremyDover (on 28. November 2022, 23:35) | 21 | 99 % |
| Embraced by Qodec (on 6. November 2020, 18:56) | 66 | 97 % |
| Chaos Construction: Battlefield by Jesper (on 16. December 2021, 13:25) | 57 | 100 % |
| Shikasudoku 2 by Qodec (on 12. February 2022, 12:09) | 55 | 95 % |
| Dutch Baby - a Snake Egg Sudoku by glum_hippo (on 13. January 2024, 07:17) | 68 | 96 % |
| Yin-yang Anti-Knight by Tom1i (on 30. April 2020, 21:59) | 14 | 96 % |
| 3D Killer Sudoku by SlowLarry (on 21. May 2020, 17:32) | 18 | 96 % |
| Wichtel 2020 (10): Vier Wichtel, vier Viertel by wichtel (on 5. October 2021, 02:02) | 26 | 99 % |
| Arrows Anonymous by XeonRisq (on 11. March 2022, 04:00) | 12 | 98 % |
