(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 | |
|---|---|---|---|
 | King's Gambit by GemmaOane (on 2. August 2023, 19:12) | 89 |  95 % |
| Pseudoscience by marty_sears (on 7. February 2024, 19:54) | 161 | 97 % |
| Negative X plus V by TheGreatGoatsbie (on 7. August 2024, 20:10) | 108 | 94 % |
| Six-pack Linked Sudokus #4 by Genomico (on 12. March 2021, 01:16) | 75 | 99 % |
| Cosmic Balance (FoW) by Nurator (on 20. January 2024, 20:16) | 176 | 96 % |
| Gravity Sudoku by Cane_Puzzles (on 15. February 2021, 16:49) | 20 | 99 % |
| Bálint Kopasz (Tokyo 2020) by Lisztes (on 5. August 2021, 00:46) | 26 | 91 % |
| Caught Between Enemy Lines by Playmaker6174 (on 14. August 2021, 10:07) | 24 | 95 % |
| Mutant Fillomino by au voleur! (on 19. February 2022, 18:03) | 23 | 94 % |
| T Time by EricRathbun (on 23. March 2022, 21:44) | 25 | 96 % |
| Narwhal by Xenonetix (on 29. June 2022, 22:22) | 48 | 98 % |
| Squeez Theorem (Suguru Deconstruction) by KevinTheMH (on 28. June 2023, 21:33) | 25 | 95 % |
| Diagonalization (Partial CC) by the_cogito (on 31. July 2023, 15:45) | 24 | 99 % |
| Knight's Kropki by Scruffamudda (on 12. August 2023, 06:13) | 27 | 99 % |
| Different Differences by marty_sears (on 21. October 2023, 19:43) | 95 | 94 % |
| A Killer Palindrome Sudoku by by81996672 (on 26. December 2023, 08:35) | 27 | 93 % |
| Quantum Irregularities by gdc (on 29. June 2024, 19:13) | 45 | 95 % |
| Retraces by arbitrary (on 6. September 2024, 00:07) | 50 | 95 % |
| Chaotic Evil by mathpesto (on 29. April 2022, 00:00) | 124 | 98 % |
| Killer X Sudoku by ICHTUES (on 9. May 2021, 06:00) | 51 | 96 % |
