(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 | |
|---|---|---|---|
 | Entropic Arena by Raumplaner (on 16. October 2022, 12:07) | 37 |  92 % |
| Adulthood by GarlicBredFries (on 5. March 2023, 05:42) | 34 | 95 % |
| Pune by MavericksJD (on 30. March 2023, 12:51) | 107 | 98 % |
| 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 % |
| A Hero Emerges by Joseph nehme (on 29. August 2024, 08:04) | 97 | 90 % |
| Stay in Your Box by marty_sears (on 2. February 2025, 03:58) | 178 | 97 % |
| Stabelle by ICHTUES (on 14. August 2023, 11:00) | 102 | 97 % |
| Milestones by marty_sears (on 5. October 2024, 19:14) | 176 | 98 % |
| 10-in-9 killer sudoku #1 by Nylimb (on 25. January 2020, 15:20) | 58 | 95 % |
| Every Third Knight by JeremyDover (on 4. February 2022, 17:00) | 92 | 93 % |
| Crosswalk by zetamath (on 3. March 2024, 19:32) | 130 | 96 % |
| 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 % |
