(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 | |
|---|---|---|---|
 | Carnivorous Pansy by PjotrV (on 10. April 2021, 09:22) | 19 |  95 % |
| Two Faced Coin - Doubling Lines Twist by purpl (on 16. September 2021, 17:59) | 15 | 92 % |
| Masyudoku by Testarossa (on 26. September 2021, 12:35) | 24 | 96 % |
| x-sums and n-cycles by mathpesto (on 7. January 2022, 03:37) | 14 | 96 % |
| The Knights Who Say "Negator" by Scojo (on 17. September 2023, 06:41) | 19 | 98 % |
| Never 4 by Jrosas (on 6. May 2024, 18:49) | 25 | 93 % |
| Antiknight Thermo Sudoku by dgreenspan (on 22. July 2020, 22:40) | 47 | 93 % |
| Synthesis (Killer/Renban/Antiknight) by dumediat (on 29. June 2023, 00:35) | 72 | 93 % |
| Es war einmal eine geheime Schrift by berni (on 1. November 2008, 15:56) | 77 | 92 % |
| Pentopia Rundweg by tuace (on 22. April 2019, 09:55) | 63 | 98 % |
| The Secret Does Not Apply by Niverio (on 27. February 2022, 12:34) | 38 | 98 % |
| Homebound Sandwich Sudoku by Sebastian Losch (on 25. April 2020, 21:37) | 18 | 94 % |
| Gossiping Queens on 7x7 Torus by SudokuExplorer (on 10. September 2020, 17:44) | 16 | 93 % |
| Sandwich Sudoku--春卷 by cdwg2000 (on 30. October 2020, 13:56) | 18 | 91 % |
| Mystery Sandwiches or X-Sums by UnnamedSorcerer (on 18. November 2020, 01:59) | 15 | 96 % |
| Triplet Sums by Realshaggy (on 27. January 2021, 23:59) | 30 | 93 % |
| Distant Relations #2 by Big Tiger (on 13. March 2021, 06:27) | 14 | 93 % |
| Maria by dennischen (on 9. March 2024, 06:46) | 47 | 92 % |
| Gerade-Ungerade-Killer III by Realshaggy (on 17. September 2013, 11:31) | 83 | 95 % |
| Solver, there's a fly on my Sudoku! by IcyFruit (on 25. November 2023, 22:39) | 99 | 96 % |
