(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 | |
|---|---|---|---|
 | Richard's Bouncy Castle Birthday Party by Lizzy01 (on 23. February 2025, 00:55) | 41 |  97 % |
| Hexaoctoquadri by mathpesto (on 20. March 2025, 16:05) | 44 | 96 % |
| Cutthroat by NicoD (on 4. April 2025, 05:17) | 20 | 92 % |
| Constantinople (U-Bahn with Nesting Clues) by sfushidahardy (on 23. August 2025, 00:31) | 24 | 100 % |
| Konami Code by TotallyNormalCat (on 10. March 2021, 23:30) | 101 | 97 % |
| Entropy Minimalism by Mad-Tyas (on 10. January 2022, 13:01) | 81 | 96 % |
| Anti-Knight Killer Sudoku #3 by Phistomefel (on 11. February 2021, 23:20) | 121 | 95 % |
| Drunken Knights by Blobz (on 8. July 2022, 16:00) | 71 | 95 % |
| King Arthur by oxjphs (on 13. August 2023, 06:37) | 65 | 95 % |
| Classic Thermo Sudoku by Phistomefel (on 2. February 2021, 22:33) | 108 | 95 % |
| Vierter Pfeilchenstrauß by glum_hippo (on 4. November 2020, 15:53) | 45 | 99 % |
| When X-Sums meet Killer by Joseph nehme (on 8. February 2021, 14:36) | 36 | 96 % |
| 9 Cages by DVFrank (on 4. October 2021, 23:25) | 40 | 98 % |
| Nurimisaki Sudoku - Whispers by Mark Sweep (on 9. November 2022, 16:15) | 43 | 95 % |
| U-Bahn with Empty Clues (3) by KNT (on 27. July 2023, 04:46) | 74 | 99 % |
| X-Count Mod 3 Sudoku by Timwi (on 2. May 2020, 05:21) | 18 | 90 % |
| Galaxy Killer Key-Clone Sudoku by ahaupt (on 26. May 2020, 18:02) | 21 | 95 % |
| Parity Party XVI, "Block Party" by glum_hippo (on 4. March 2021, 05:54) | 18 | 95 % |
| Reservation for Eight by apiyo (on 25. March 2021, 09:16) | 20 | 97 % |
| Tellurium Chaos by Nityant5 (on 12. May 2021, 13:02) | 73 | 100 % |
