(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 | |
|---|---|---|---|
 | Loose associations (Numbered rooms/Remote sums/Region sum lines) by dumediat (on 6. October 2023, 21:39) | 56 |  93 % |
| the herding party by aqjhs (on 8. October 2025, 05:32) | 17 | 94 % |
| X---V*8 by NurglesGift (on 17. August 2025, 16:10) | 50 | 93 % |
| nabneR by zetamath (on 4. July 2021, 17:35) | 69 | 98 % |
| Japanese Sums Sudoku - with negatives by RockyRoer (on 4. September 2023, 14:33) | 30 | 97 % |
| Wichtels Rätselsommer 2024 (8): Kakuro-Messfehler by wichtel (on 17. September 2024, 20:23) | 31 | 99 % |
| Equality Cages by Big Tiger (on 29. May 2021, 00:24) | 21 | 98 % |
| Sigma Pi by IcyFruit (on 7. December 2023, 21:50) | 104 | 93 % |
| Happy Birthday Piatato: A Doppelblock U-Bahn by wisty (on 30. August 2023, 03:33) | 38 | 99 % |
| Quantum Balance (by gdc?) by gdc (on 19. September 2025, 17:38) | 42 | 99 % |
| Grow outside the grid by Lizzy01 (on 8. February 2025, 01:24) | 14 | 92 % |
| Zombie! (Araf + Yin-Yang) by sfushidahardy (on 13. April 2025, 17:06) | 63 | 96 % |
| Chiaroscuro U-Bahn by yttrio (on 17. May 2025, 01:40) | 31 | 95 % |
| Border Count Pentominous by Gliperal (on 13. March 2023, 00:08) | 36 | 92 % |
| JCQ #5: Fawlty Towers (Liar Thermo Killer Sudoku) by peterchayward (on 17. July 2020, 11:13) | 55 | 96 % |
| Myriad of Triad by Tyrgannus (on 18. April 2021, 22:04) | 32 | 94 % |
| A Latin Earthquake by PrimeWeasel (on 15. April 2022, 22:56) | 20 | 97 % |
| Adventskalender 2025, Türchen 24 - Rundweg by Zzzyxas (on 24. December 2025, 07:00) | 23 | 96 % |
| Sudoku Variants Series (323) - Killer Kropki Sudoku by Richard (on 2. June 2021, 00:00) | 76 | 96 % |
| Building Regions in Fog of War: Border Patrol 1 by Jeet Sampat (on 23. March 2024, 17:59) | 42 | 91 % |
