(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 | |
|---|---|---|---|
 | XY-Differences III by glum_hippo (on 14. July 2020, 02:12) | 48 |  91 % |
| The Snake Nest by matt383 (on 9. October 2020, 14:03) | 40 | 98 % |
| The Corners Are Even - Arrow Odd/Even Sudoku by Mr.Menace (on 2. February 2022, 23:04) | 39 | 96 % |
| Lawful Wrogn by Niverio (on 20. March 2023, 16:33) | 84 | 95 % |
| Quincies by lerroyy (on 11. June 2023, 19:14) | 38 | 92 % |
| Faultline (Filloku #4) by mormagli (on 12. October 2023, 20:15) | 38 | 97 % |
| Nonconsecutive Killer Sudoku by spxtr (on 1. January 2021, 06:21) | 106 | 96 % |
| Blueprints (ft. Andrewsarchus) by Nordy (on 14. May 2025, 09:00) | 86 | 99 % |
| Parity Parity by vitaminz (on 3. July 2025, 15:18) | 91 | 95 % |
| Killer Sudoku - Dirty Tricks by DiMono (on 25. November 2020, 16:27) | 50 | 97 % |
| Fill-a-Renban by SSG (on 23. July 2023, 07:22) | 42 | 95 % |
| Zeta's Nightmare by zetamath (on 15. October 2021, 15:42) | 51 | 97 % |
| Chaos Construction by Phistomefel (on 21. April 2020, 00:27) | 150 | 97 % |
| Nurikiller 2 by mathpesto (on 4. April 2023, 13:53) | 79 | 100 % |
| Clock Faces Sudoku by Phistomefel (on 21. August 2020, 16:50) | 38 | 92 % |
| 真笑Puzzles023--N-Sums Sudoku--Counter by cdwg2000 (on 5. February 2021, 17:45) | 29 | 100 % |
| Wichtel 2020 (3): Wichtel beim Glühwein by wichtel (on 10. April 2021, 00:22) | 22 | 97 % |
| Arrows and Palindromes - II by tenaliraman (on 18. April 2021, 21:22) | 27 | 91 % |
| Palindromaze by FinnishGuy (on 14. September 2021, 20:25) | 30 | 90 % |
| Exploded Sum Compass Sudoku by stephane.bura (on 31. January 2022, 21:00) | 10 | 100 % |
