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 | |
|---|---|---|---|
![]() | OutsideTheUsula by Palfly Kampling (on 4. July 2023, 01:47) | 53 | ![]() 91 % |
![]() | 1918 by starwarigami (on 19. October 2023, 11:29) | 57 | ![]() 96 % |
![]() | Infancy by Myxo (on 14. November 2022, 14:27) | 117 | ![]() 97 % |
![]() | VvVwVvV by NicoD (on 15. July 2025, 05:30) | 79 | ![]() 94 % |
![]() | Galaxies Collide by Prof.Dori (on 3. April 2024, 15:31) | 84 | ![]() 98 % |
![]() | Counterpoint (Renban Arrow) by tallcat (on 16. July 2022, 08:30) | 91 | ![]() 97 % |
![]() | Chaotic X-Sums by Florian Wortmann (on 6. September 2023, 18:09) | 125 | ![]() 97 % |
![]() | Milchstraße (Sektor 23C) by usp (on 5. November 2014, 00:00) | 40 | ![]() 95 % |
![]() | Entwined Sandwiches Sudoku by matt383 (on 7. April 2020, 17:25) | 44 | ![]() 97 % |
![]() | ZIRKUS - buntes Buchstabenrätsel / colorful letter puzzle by DocLogic (on 30. April 2020, 22:59) | 33 | ![]() 98 % |
![]() | Skyscraper Aquarium Sudoku by Sam Knott (on 23. June 2020, 18:01) | 32 | ![]() 96 % |
![]() | 10-in-9 CLXVI sudoku by Nylimb (on 21. October 2020, 20:10) | 15 | ![]() 94 % |
![]() | Disjoint Killer Arrows by Joseph nehme (on 13. December 2020, 17:11) | 30 | ![]() 96 % |
![]() | Compass Sudoku by stephane.bura (on 25. December 2020, 00:00) | 45 | ![]() 99 % |
![]() | Primality Party by abed hawila (on 12. March 2021, 15:44) | 13 | ![]() 96 % |
![]() | XY-Differences and -Sums by glum_hippo (on 30. April 2021, 06:00) | 17 | ![]() 98 % |
![]() | X-Box 180 by zegres (on 24. January 2022, 05:43) | 45 | ![]() 97 % |
![]() | Knighten by Testarossa (on 24. January 2022, 21:37) | 81 | ![]() 95 % |
![]() | The Andromeda Chain (Spiral Galaxies, Lockout Lines) by Chilly (on 8. February 2022, 16:08) | 13 | ![]() 98 % |
![]() | Van Helsing by the_cogito (on 8. February 2022, 17:40) | 28 | ![]() 97 % |