(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 | |
|---|---|---|---|
 | Killer Wasp by Quarterthru (on 31. May 2021, 12:00) | 31 |  97 % |
| Arrows and a Big X by GBPack (on 17. June 2021, 17:11) | 29 | 97 % |
| Stacked - Arrow Sudoku by Mr.Menace (on 6. July 2021, 20:51) | 49 | 97 % |
| Multiple Signs by tesseralis (on 9. June 2022, 01:20) | 32 | 97 % |
| Room Service by Xenonetix (on 9. October 2022, 02:02) | 27 | 93 % |
| Distinctiveness by Ridhwan (on 12. February 2024, 00:05) | 26 | 92 % |
| Echoing Cages by graggle (on 26. April 2025, 11:00) | 59 | 96 % |
| Kakuro-Suguru Chaos Construction by mathpesto (on 25. January 2023, 20:05) | 94 | 97 % |
| Japanische Hochhaus-Summen (Mini-Krypto) by ibag (on 21. September 2012, 22:04) | 56 | 98 % |
| Wichtel 2019 (9): Hybrid by wichtel (on 4. October 2020, 19:02) | 36 | 99 % |
| Areal Sudoku by ICHTUES (on 4. February 2021, 12:26) | 76 | 95 % |
| Seilkunde by Blashyrkh (on 16. May 2024, 17:40) | 39 | 96 % |
| Mystery Cages Somedoku by blackjackfitz (on 18. September 2024, 01:13) | 37 | 90 % |
| Halligen by KNT (on 8. January 2023, 07:48) | 43 | 99 % |
| Misdirection by MicroStudy (on 24. May 2023, 15:31) | 43 | 95 % |
| Philly by zetamath (on 8. July 2024, 01:14) | 48 | 94 % |
| Four Corners (Arrow Killer X) by tallcat (on 13. May 2021, 15:02) | 96 | 98 % |
| 159 German Whispers Sudoku by Qodec (on 19. November 2021, 18:19) | 100 | 97 % |
| Six-pack Linked Sudokus #2 by Genomico (on 4. October 2020, 16:49) | 57 | 98 % |
| Quiet, please! (renban whispers sudoku) A.k.a. "The Pipe" by Lizzy01 (on 18. August 2022, 20:51) | 52 | 98 % |
