(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 | |
|---|---|---|---|
 | Safe Distances by Emphyrio (on 26. September 2022, 16:54) | 42 |  92 % |
| Going in Circles by antiknight (on 1. December 2022, 15:06) | 37 | 95 % |
| Half Life (Yin Yang Deconstruction) by Agent (on 30. August 2022, 09:00) | 73 | 100 % |
| Rising Arrow Sudoku - Halloween Crab by DiMono (on 3. June 2021, 18:26) | 49 | 97 % |
| Killer Windrad by tuace (on 30. July 2016, 14:45) | 44 | 98 % |
| Roller Coaster mit Extras 11 by Uhu (on 11. October 2018, 18:15) | 49 | 97 % |
| Die Kryptos - S04E05: U-Bahn unter Hochhäusern by tuace (on 21. January 2020, 08:06) | 45 | 100 % |
| Chaos Construction: X-Sums / Sandwich by KNT (on 13. April 2022, 17:12) | 56 | 97 % |
| Millstone by jwsinclair (on 13. June 2024, 20:59) | 67 | 97 % |
| The Buddy System by Allagem (on 20. June 2024, 07:55) | 74 | 98 % |
| Chaotic Equality by Knickolas (on 8. December 2022, 21:07) | 74 | 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) | 37 | 99 % |
| Machtwechsel in Rätselhausen by Statistica (on 1. December 2018, 18:18) | 30 | 99 % |
| 10-in-9 killer sudoku #3 by Nylimb (on 11. February 2020, 22:35) | 43 | 99 % |
| Assorted Sandwiches Sudoku by stephane.bura (on 15. June 2020, 14:37) | 14 | 93 % |
| Skyscrapers 10x10 by pandiani42 (on 6. August 2020, 12:42) | 22 | 97 % |
| 真笑Puzzles007:Bachelor(光棍) Sudoku02 by cdwg2000 (on 23. December 2020, 22:43) | 14 | 91 % |
| XY-Differences VI, "Delimited Edition" by glum_hippo (on 4. February 2021, 20:09) | 24 | 99 % |
