(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 | |
|---|---|---|---|
 | Modular Fillomino by mathpesto (on 16. November 2024, 03:08) | 105 |  98 % |
| 10-in-9 Isolation Sudoku by Phistomefel (on 5. April 2020, 12:07) | 44 | 97 % |
| Sirius by jovi_al (on 19. February 2022, 03:07) | 41 | 98 % |
| Stairity - Chaos Construction by the_cogito (on 10. August 2022, 03:07) | 88 | 98 % |
| Safe Distances by Emphyrio (on 26. September 2022, 16:54) | 46 | 93 % |
| Perfectly Balanced by IcyFruit (on 13. February 2025, 14:33) | 86 | 97 % |
| Ten Ring Circus by JeffWajes (on 30. December 2025, 06:27) | 100 | 97 % |
| Displacement (Arrow Sudoku) by Phistomefel (on 10. May 2022, 19:07) | 102 | 98 % |
| Prime-Co Sweepers by XeonRisq (on 11. January 2023, 17:00) | 48 | 100 % |
| Pack of Aces by mormagli (on 8. February 2024, 02:20) | 52 | 96 % |
| Pointed Chaos by yttrio (on 30. June 2023, 20:03) | 107 | 98 % |
| Heqtare by mathpesto (on 2. September 2022, 18:31) | 57 | 99 % |
| Teenage Dream by starwarigami (on 6. September 2022, 07:37) | 57 | 97 % |
| Ancient Ruins (Fog, BYO Killer, Nurikabe) by lepton (on 6. February 2023, 16:24) | 66 | 95 % |
| Venn Diagram Loops by Prof.Dori (on 9. May 2024, 16:44) | 51 | 99 % |
| The Usual Suspects by zetamath (on 22. October 2021, 02:39) | 78 | 98 % |
| Japanese Aquarium by Jay Dyer (on 3. January 2023, 23:06) | 67 | 99 % |
| Beyond (Nurikabe Sudoku) by MaizeGator (on 15. July 2025, 20:10) | 85 | 97 % |
| Suguru Chaos Deconstruction #3: Whispering Palindromes by mathpesto (on 20. February 2022, 16:27) | 116 | 98 % |
| Verrätselte Zahlenfolge by berni (on 30. March 2011, 21:27) | 31 | 97 % |
