(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 | |
|---|---|---|---|
 | Whispers + Arrows + Renban + Sudoku X by Jeet Sampat (on 14. December 2022, 13:15) | 55 |  96 % |
| Three of Diamonds by zetamath (on 20. February 2023, 16:07) | 52 | 93 % |
| Aquarium Fillomino by wooferzfg (on 4. September 2023, 19:58) | 26 | 100 % |
| Biloxi - a Beachcomber Sudoku by glum_hippo (on 23. November 2023, 02:00) | 22 | 98 % |
| Thirteen Ghosts by mathpesto (on 19. September 2024, 22:37) | 49 | 99 % |
| Palindrome Killer Sudoku by udukos (on 8. August 2020, 23:02) | 40 | 94 % |
| Witchcraft by PotatoHead21 (on 25. November 2021, 21:56) | 38 | 98 % |
| Extraterrestrial Tripleblock with X-Sums by KNT (on 27. May 2023, 16:45) | 34 | 100 % |
| Chaotic Pointers by arbitrary (on 7. December 2024, 23:49) | 35 | 94 % |
| Archers Defending the Castle by GBPack (on 9. May 2021, 06:41) | 51 | 99 % |
| Neighbors Sudoku by Gliperal (on 26. June 2022, 14:51) | 80 | 96 % |
| Different, But Still Wrogn by DiMono (on 3. June 2022, 23:39) | 80 | 97 % |
| Marco Polo (Loop Deconstruction) by Agent (on 6. June 2023, 09:00) | 90 | 98 % |
| Sprengungen im Hochhausviertel II by tuace (on 18. January 2015, 23:36) | 38 | 98 % |
| Assorted Sandwiches Sudoku by stephane.bura (on 15. June 2020, 14:37) | 15 | 93 % |
| Confetti Sums Killer Sudoku by Jesper (on 24. February 2021, 15:10) | 43 | 98 % |
| Propellers by fritzdis (on 6. March 2021, 15:35) | 52 | 98 % |
| Arrow Sudoku by PotatoHead21 (on 26. April 2021, 09:02) | 26 | 98 % |
| Pentominoes Intersection by RockyRoer (on 13. September 2021, 00:54) | 26 | 99 % |
| Parity Paradigm by grkles (on 31. December 2021, 13:42) | 24 | 99 % |
