(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 | |
|---|---|---|---|
 | The Song of the Serpent and the Wanderer - A tribute to Nordy by damasosos92 (on 17. July 2023, 03:40) | 61 |  94 % |
| Nikolaus Challenge by Luigi (on 6. December 2009, 06:12) | 14 | 94 % |
| Verhexte Sudukte by Menxar (on 19. September 2017, 12:53) | 28 | 98 % |
| Rainy Day Sudoku 12 (squared) & 35 by joecat (on 30. July 2020, 11:20) | 36 | 100 % |
| Wichtel 2019 (7): Die mutierte Sieben by wichtel (on 14. September 2020, 18:12) | 25 | 99 % |
| -45 Killer by Mesmer (on 21. August 2020, 14:39) | 14 | 98 % |
| Just between the N of us by Sktx (on 4. June 2021, 12:38) | 12 | 98 % |
| Couples by kolot (on 28. July 2021, 14:07) | 25 | 99 % |
| The Gap by ICHTUES (on 5. December 2021, 06:00) | 19 | 90 % |
| Chaos Construction: Border Sums by kolot (on 1. February 2022, 17:06) | 67 | 99 % |
| Sudoku O.W.L. by Nahileon (on 10. October 2022, 21:25) | 20 | 100 % |
| Knot in the Crosshairs by antiknight (on 13. December 2022, 23:40) | 24 | 96 % |
| Trident by randall (on 6. January 2023, 23:46) | 15 | 94 % |
| Second Region X-Sums Chaos #2 by Elliptical (on 18. January 2023, 22:58) | 14 | 94 % |
| Rollercoaster Deconstruction by tallcat (on 3. April 2023, 20:36) | 57 | 97 % |
| Wildflowers by mathpesto (on 28. May 2023, 18:09) | 69 | 95 % |
| A Flock of Pixels (Colourful Killers) by The Book Wyrm (on 27. August 2023, 15:56) | 12 | 98 % |
| Confetti by Ennead (on 17. September 2023, 16:38) | 23 | 100 % |
| Double Loop Japanese Sums by Agent (on 26. February 2024, 09:00) | 23 | 94 % |
| Clockwork Yajilin: Blackout Cipher by wisty (on 19. March 2024, 22:26) | 13 | 96 % |
