(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 | |
|---|---|---|---|
 | 10-in-9 killer sudoku #1 by Nylimb (on 25. January 2020, 15:20) | 58 |  95 % |
| X*Cage by NurglesGift (on 27. November 2024, 18:14) | 151 | 94 % |
| Japanische Summen mit Querverweisen by ibag (on 23. December 2011, 21:31) | 73 | 98 % |
| Every Third Knight by JeremyDover (on 4. February 2022, 17:00) | 93 | 93 % |
| Dreams by Zibl (on 15. November 2025, 19:06) | 99 | 98 % |
| Crosswalk by zetamath (on 3. March 2024, 19:32) | 130 | 96 % |
| Sudoku Variants Series (033) - Little Killer by Richard (on 15. July 2014, 00:00) | 185 | 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) | 25 | 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 % |
| Find the killer by lerroyy (on 3. January 2022, 11:06) | 14 | 91 % |
| Seven Arrow Carpet Sudoku by jackisaacbryan (on 22. March 2022, 20:34) | 16 | 90 % |
| Wings by Sabrar (on 7. June 2022, 16:17) | 14 | 90 % |
| Colorguru Chaos Deconstruction: Renbans by crispy16 (on 23. June 2022, 05:33) | 27 | 99 % |
