(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 | |
|---|---|---|---|
 | The Weird E-key by ebiggie (on 6. August 2025, 22:07) | 15 |  93 % |
| What The Flecks?! by NicoD (on 31. August 2025, 05:30) | 64 | 93 % |
| Shuffledoku by Kaktuslav (on 31. October 2025, 08:00) | 15 | 98 % |
| Twin Killer Sudoku 2008-2009 by Richard (on 1. January 2009, 00:01) | 169 | 93 % |
| Ben Nevis (Killer) by tallcat (on 30. December 2023, 13:50) | 106 | 97 % |
| Killer Sudoku - Progress City by DiMono (on 14. September 2020, 01:27) | 69 | 97 % |
| Little Killer Sudoku by trivial171 (on 11. May 2020, 00:46) | 55 | 95 % |
| Tilting by SSG (on 2. June 2022, 07:03) | 48 | 100 % |
| Thermosn8kes by Nordy (on 5. August 2022, 08:00) | 56 | 95 % |
| Somedokus Are Friendly Dokus by juggler (on 15. April 2024, 20:39) | 50 | 96 % |
| Wichtel 2015 (9): Das Amulett by wichtel (on 6. June 2016, 15:20) | 35 | 97 % |
| Eye of the Beholder by Skunkworks (on 5. June 2022, 01:50) | 38 | 90 % |
| Way out of my way by PrimeWeasel (on 1. September 2022, 20:36) | 38 | 93 % |
| Road and River (Palindrome and Thermo-Region Sum Line) by BenTen (on 26. May 2023, 00:35) | 46 | 93 % |
| U-Bahn 2 by wooferzfg (on 6. June 2025, 07:30) | 37 | 97 % |
| Uraninite (Killer cages, Odd/Even) by Bellsita (on 24. July 2024, 20:22) | 95 | 93 % |
| Ubiquitous by NicoD (on 14. February 2026, 05:30) | 60 | 97 % |
| German Whispers Sandwich Sudoku by Jesper (on 4. July 2020, 11:47) | 82 | 96 % |
| Toroidal Chess Sudoku #2 by Rotstein (on 7. June 2020, 20:24) | 26 | 92 % |
| 2X45 by Lisztes (on 22. October 2021, 01:00) | 28 | 92 % |
