(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 | |
|---|---|---|---|
 | 200 Light-years to Zetamath (Black Hole) by heliopolix (on 27. August 2023, 19:02) | 38 |  96 % |
| Trick 17 by Mad-Tyas (on 12. December 2023, 12:12) | 67 | 97 % |
| Stay in Your Box by marty_sears (on 2. February 2025, 03:58) | 170 | 97 % |
| A Hero Emerges by Joseph nehme (on 29. August 2024, 08:04) | 97 | 90 % |
| 10-in-9 killer sudoku #1 by Nylimb (on 25. January 2020, 15:20) | 58 | 95 % |
| Penghu County by Myxo (on 13. May 2025, 18:44) | 140 | 97 % |
| Sudoku Variants Series (033) - Little Killer by Richard (on 15. July 2014, 00:00) | 180 | 95 % |
| Toroidal Chess Sudoku #4 - Queens by Rotstein (on 14. June 2020, 18:44) | 15 | 90 % |
| 12x12 Yajilin / Skyscrapers by stefliew (on 21. July 2020, 18:30) | 28 | 94 % |
| Akari Sudoku by Ringo (on 10. August 2020, 12:27) | 15 | 95 % |
| Skyscrapers 9*9 by cdwg2000 (on 12. September 2020, 18:37) | 47 | 95 % |
| Happy New Year 2021 (Sudoku) by Hackiisan (on 31. December 2020, 08:46) | 33 | 92 % |
| Parity Party XVII, "Zum Selberbasteln" by glum_hippo (on 10. March 2021, 06:00) | 24 | 98 % |
| Sudo-Cube by XeonRisq (on 30. August 2021, 00:00) | 42 | 93 % |
| Die Bahn ist immer noch pünktlich, by Dandelo (on 7. September 2021, 23:05) | 11 | 95 % |
| Mantis by Tyrgannus (on 14. September 2021, 01:08) | 33 | 93 % |
| Sudoku Variants Series (347) - Sudoku Connon by Richard (on 17. November 2021, 00:00) | 65 | 97 % |
| 3's Company by the_cogito (on 30. November 2021, 20:00) | 11 | 100 % |
| Seven Arrow Carpet Sudoku by jackisaacbryan (on 22. March 2022, 20:34) | 15 | 90 % |
| Wings by Sabrar (on 7. June 2022, 16:17) | 13 | 90 % |
