(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 | |
|---|---|---|---|
 | Yin Yang Arrows by yttrio (on 13. October 2023, 23:06) | 125 |  98 % |
| Fly Away on my Ziffer by DubiousMobius (on 7. August 2024, 11:54) | 22 | 97 % |
| Reversing Valve (Dynamic Fog Edition) by ViKingPrime (on 4. June 2025, 15:56) | 52 | 93 % |
| Floodwaters by Jay Dyer (on 9. July 2022, 00:45) | 73 | 97 % |
| Sashigane Sudoku by Ambrose (on 14. November 2022, 14:06) | 75 | 97 % |
| Japanische Summen-Höhle 2358 by Uhu (on 1. August 2017, 22:32) | 48 | 98 % |
| Coloring Book #9: The Corridor by blackjackfitz (on 23. October 2024, 17:05) | 133 | 97 % |
| Even Trios Killer Sudoku by Quarterthru (on 14. September 2020, 12:00) | 33 | 98 % |
| Short THERM 12+1 by Lisztes (on 13. November 2020, 01:00) | 33 | 90 % |
| BLT by zetamath (on 19. June 2021, 20:30) | 32 | 98 % |
| Irregional by riffclown (on 2. April 2022, 19:21) | 32 | 93 % |
| Prime Party by Realshaggy (on 22. September 2022, 01:17) | 29 | 95 % |
| Variety (6x6 Sudoku Pack) by Florian Wortmann (on 6. June 2024, 12:56) | 35 | 97 % |
| ABENNR by FullDeck-Missing (on 14. November 2024, 06:20) | 73 | 95 % |
| Shenanigans by Jay Dyer (on 9. May 2023, 17:11) | 172 | 98 % |
| Thermography by arbitrary (on 12. December 2023, 16:22) | 76 | 95 % |
| Counting Reflections by Jolly Rogers (on 18. September 2025, 18:35) | 78 | 95 % |
| Koralle (5) by Uhu (on 8. November 2020, 11:15) | 38 | 91 % |
| Juggernaut by Andrewsarchus (on 23. October 2022, 22:20) | 43 | 92 % |
| SudokOops by Abdul the Killer (on 2. November 2022, 16:52) | 42 | 91 % |
