(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 | |
|---|---|---|---|
 | German Sandwiches by Scruffamudda (on 16. March 2022, 07:34) | 39 |  98 % |
| Vertigo Yajilin #1 by Piatato (on 10. April 2024, 00:37) | 37 | 98 % |
| Dishes Washed by timotab (on 25. May 2024, 15:59) | 45 | 90 % |
| [New Constraint] Entropy Sudoku by Mad-Tyas (on 3. December 2021, 05:28) | 133 | 93 % |
| Bäume im Herbst: Mini-Höhle by r45 (on 7. November 2019, 20:00) | 38 | 98 % |
| Ghost Python 2 (Clone Snake Sudoku) by peterchayward (on 29. July 2020, 19:16) | 46 | 95 % |
| Shuffled by jwsinclair (on 28. November 2023, 21:19) | 50 | 93 % |
| Cross The Streams by Uhu (on 3. August 2024, 21:19) | 40 | 96 % |
| Odd Couples Killer Sudoku by Quarterthru (on 29. August 2020, 12:00) | 46 | 95 % |
| Fillomino-Yajilin-Tapa by CJK (on 4. April 2021, 21:15) | 106 | 100 % |
| Whispers in the Night by ___ (on 13. June 2021, 05:24) | 59 | 95 % |
| Speed Up by ademjaz (on 6. October 2022, 11:04) | 52 | 96 % |
| Hammerhead Shark by Lizzy01 (on 18. February 2025, 16:28) | 60 | 92 % |
| Pointing Down by Visumation (on 22. October 2024, 11:56) | 55 | 91 % |
| Sudoku Variants Series (179) - Outside Killer Sudoku by Richard (on 2. May 2017, 00:00) | 108 | 95 % |
| Alien X-Sums Sudoku by Realshaggy (on 11. November 2022, 12:15) | 55 | 92 % |
| Chaos Construc-to-N by mellowrobinson (on 15. October 2025, 20:10) | 184 | 97 % |
| Skyscraper, Arrow, and Killer by old thousand (on 3. October 2022, 04:30) | 59 | 92 % |
| Diamonds are Forever by Sartor (on 24. November 2025, 16:26) | 74 | 93 % |
| 11x11 Classic Star Battle by Phistomefel (on 19. August 2020, 19:31) | 183 | 93 % |
