(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 Windrad by tuace (on 30. July 2016, 14:45) | 44 |  98 % |
| Lighthouses by IcyFruit (on 2. October 2025, 12:26) | 121 | 91 % |
| X Zip Line by antiknight (on 29. November 2023, 19:36) | 54 | 96 % |
| Snakes of Chaos by Andrewsarchus (on 14. January 2025, 15:59) | 114 | 99 % |
| Sudoku Variants Series (373) - Four Winds Killer by Richard (on 1. June 2022, 01:00) | 62 | 93 % |
| Killer - Region Sum Lines - Cave by abed hawila (on 9. May 2022, 20:41) | 69 | 100 % |
| Ma'at's Judgement - The Weighing of the Heart (Chaos Construction) by Chilly (on 22. November 2022, 16:58) | 82 | 100 % |
| Leakage by Testarossa (on 21. January 2023, 20:10) | 81 | 100 % |
| 1. Teil der Trilogie: Ein verliebter Rundweg by berni (on 28. September 2010, 12:34) | 76 | 98 % |
| Zoom Out by Myxo (on 30. July 2024, 12:22) | 115 | 99 % |
| The Wall by juggler (on 5. June 2025, 19:37) | 131 | 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 % |
| 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) | 47 | 99 % |
| arROw SudOkU by filuta (on 1. March 2021, 18:08) | 28 | 91 % |
