(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 | |
|---|---|---|---|
 | 1. Teil der Trilogie: Ein verliebter Rundweg by berni (on 28. September 2010, 12:34) | 76 |  98 % |
| Yin-Yang-Yong by marty_sears (on 13. May 2024, 00:27) | 93 | 96 % |
| Zoom Out by Myxo (on 30. July 2024, 12:22) | 115 | 99 % |
| Snakes of Chaos by Andrewsarchus (on 14. January 2025, 15:59) | 116 | 99 % |
| The Wall by juggler (on 5. June 2025, 19:37) | 132 | 98 % |
| 5-ABCtje by Richard (on 28. August 2009, 09:01) | 65 | 90 % |
| Der verlorene Schlüssel by berni (on 5. March 2010, 14:34) | 51 | 98 % |
| Alpträume by ibag (on 27. March 2017, 23:55) | 39 | 99 % |
| Roller Coaster mit Extras 11 by Uhu (on 11. October 2018, 18:15) | 54 | 97 % |
| Wichtel 2017 (12 und Schluss): Geteilte U-Bahn by wichtel (on 24. December 2018, 10:04) | 35 | 99 % |
| Fractional 10-in-9 killer sudoku by Nylimb (on 2. April 2020, 00:11) | 22 | 96 % |
| Assorted Sandwiches Sudoku by stephane.bura (on 15. June 2020, 14:37) | 23 | 95 % |
| 4 Corners Killer Sudoku by Strosahl (on 30. September 2020, 17:20) | 35 | 94 % |
| Confetti Sums Killer Sudoku by Jesper (on 24. February 2021, 15:10) | 49 | 99 % |
| arROw SudOkU by filuta (on 1. March 2021, 18:08) | 28 | 91 % |
| Negatively Constrained Exploded Compass Sudoku by stephane.bura (on 8. March 2021, 09:00) | 19 | 94 % |
| Heterochromia (Killer Sudoku) by emmettcito (on 30. March 2021, 00:42) | 55 | 96 % |
| Little Killer by Strosahl (on 7. April 2021, 05:36) | 34 | 99 % |
| California skyscraper sudoku by Shinya (on 12. May 2021, 09:02) | 17 | 94 % |
| Palindrome Builder by Quarterthru (on 10. July 2021, 17:00) | 17 | 95 % |
