(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 | |
|---|---|---|---|
 | Serial Killers by starwarigami (on 10. April 2023, 06:44) | 89 |  97 % |
| Fog of Chaos by lepton (on 26. February 2023, 18:09) | 167 | 92 % |
| 1. Teil der Trilogie: Ein verliebter Rundweg by berni (on 28. September 2010, 12:34) | 73 | 100 % |
| Sprengungen im Hochhausviertel II by tuace (on 18. January 2015, 23:36) | 38 | 98 % |
| BYOX by randall (on 11. July 2023, 10:10) | 14 | 92 % |
| Belleville sonata (9x9, antiknight) by Breush (on 7. June 2024, 18:44) | 13 | 91 % |
| Typhon by Kafkapharnaum (on 24. August 2024, 19:41) | 12 | 98 % |
| Summation U-Bahn #5: Sorted Clues by Agent (on 22. October 2024, 09:00) | 12 | 100 % |
| Entropy Focus by Mad-Tyas (on 8. September 2022, 14:54) | 44 | 96 % |
| [Fog of War Series] 4. Labyrinth by AstralSky (on 3. November 2022, 15:51) | 52 | 91 % |
| Renban Circus by JeffWajes (on 2. September 2024, 18:54) | 45 | 94 % |
| Japanische Summen-Koralle 2358 by Uhu (on 27. December 2016, 14:23) | 52 | 98 % |
| In Between Disjoint Killings by tenaliraman (on 16. January 2021, 18:39) | 32 | 98 % |
| Cave Express (Japanese Sums Cipher) by Agent (on 21. February 2023, 09:00) | 42 | 99 % |
| Clock Faces Sudoku by Phistomefel (on 21. August 2020, 16:50) | 34 | 92 % |
| XV Sandwiches by RockyRoer (on 21. November 2020, 04:47) | 32 | 94 % |
| Palindrome Builder by Quarterthru (on 10. July 2021, 17:00) | 16 | 94 % |
| Valiant Viper in the King's Garden (Chess Snake Sudoku) by Nordy (on 5. April 2022, 01:20) | 29 | 95 % |
| Chaos Construction: diagonals by Prutsbeest (on 23. May 2022, 07:00) | 32 | 97 % |
| Loop Aquarium by wooferzfg (on 23. October 2022, 20:25) | 42 | 99 % |
