(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 | |
|---|---|---|---|
 | Vertigo Yajilin #2 by Piatato (on 7. May 2024, 17:47) | 19 |  98 % |
| Semi-Symmetry by Lizzy01 (on 20. September 2024, 11:44) | 24 | 97 % |
| A Degree in Thermology by Knickolas (on 26. November 2024, 21:51) | 44 | 97 % |
| TENtropy by Mad-Tyas (on 9. May 2023, 09:02) | 47 | 94 % |
| Neodymium (Double Cave Japanese Sums) by Agent (on 4. June 2024, 09:00) | 47 | 99 % |
| Chaos Construction: Yin Yang (9x9) by Jesper (on 22. May 2022, 10:39) | 115 | 100 % |
| Eddies by Qodec (on 12. January 2021, 22:41) | 71 | 99 % |
| Arrowings by kolot (on 25. January 2022, 11:37) | 26 | 96 % |
| Thermo Battle by 10feet (on 18. February 2022, 17:00) | 24 | 98 % |
| Regional Chaos by arbitrary (on 11. January 2025, 19:00) | 24 | 95 % |
| Saturnalia by mathpesto (on 13. January 2024, 05:19) | 87 | 93 % |
| Dynamic Duos by Niverio (on 22. August 2021, 17:32) | 51 | 98 % |
| The Cross by Tom1i (on 15. December 2020, 15:06) | 60 | 99 % |
| Chaos Fillomino - Border Gaps #2 by Mark Sweep (on 21. December 2022, 10:00) | 32 | 99 % |
| Hoverbike by tesseralis (on 10. July 2023, 04:47) | 33 | 98 % |
| Toei Subway by Myxo (on 19. February 2025, 14:05) | 31 | 100 % |
| Dismay (Region Sum Lines Sudoku) by Qodec (on 29. June 2022, 22:50) | 74 | 97 % |
| Roman Whispers (XV German Whispers Sudoku) by Phistomefel (on 31. January 2022, 18:23) | 117 | 98 % |
| Build Your Own Sloop by Piatato (on 5. July 2023, 21:23) | 39 | 98 % |
| Blind spot [Narrow Cave Sudoku Deconstruction 9x9] by Christounet (on 23. November 2023, 14:00) | 38 | 98 % |
