(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 | |
|---|---|---|---|
 | 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) | 43 | 95 % |
| Zeta's Nightmare by zetamath (on 15. October 2021, 15:42) | 51 | 97 % |
| The Moving Finger (Numbered Regions Chaos Construction) by tallcat (on 27. February 2025, 03:00) | 158 | 98 % |
| Pentomilin by Myxo (on 16. March 2025, 17:50) | 52 | 98 % |
| Leapfrog by jovi_al (on 9. April 2022, 00:30) | 68 | 96 % |
| Boxed Rooms (Chaos Construction) by thoughtbyte (on 26. August 2023, 13:01) | 63 | 96 % |
| The 4-Colour Theorem by starwarigami (on 5. February 2023, 10:00) | 77 | 96 % |
| Blueprints (ft. Andrewsarchus) by Nordy (on 14. May 2025, 09:00) | 88 | 99 % |
| Eine Koralle by matter (on 24. May 2015, 08:51) | 30 | 93 % |
| View Through The Window by SudokuExplorer (on 14. January 2021, 00:01) | 29 | 97 % |
| 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 % |
| Exploded Sum Compass Sudoku by stephane.bura (on 31. January 2022, 21:00) | 12 | 100 % |
| Sudokutown is That Way by Aaronomys (on 20. February 2022, 14:26) | 39 | 99 % |
| Chaos: Killer by lerroyy (on 11. April 2022, 20:42) | 49 | 98 % |
| Questionable Chaos (Y-sums / Skyscrapers sums chaos construction) by Lizzy01 (on 30. May 2022, 11:59) | 20 | 95 % |
| Shadow by TotallyNormalCat (on 4. July 2022, 14:00) | 42 | 98 % |
| Three Kings Go Horse Riding by Scruffamudda (on 15. August 2022, 02:19) | 19 | 93 % |
| Killer Quads by RockyRoer (on 19. September 2022, 03:14) | 47 | 100 % |
