(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 | |
|---|---|---|---|
 | Pack of Aces by mormagli (on 8. February 2024, 02:20) | 52 |  96 % |
| Heqtare by mathpesto (on 2. September 2022, 18:31) | 58 | 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) | 67 | 95 % |
| Venn Diagram Loops by Prof.Dori (on 9. May 2024, 16:44) | 53 | 99 % |
| Thorny Tie (Killer Deconstruction) by Agent (on 12. July 2022, 09:00) | 61 | 100 % |
| Cryptic Coin (Arrow Kropki Sudoku) (ft. Tyrgannus) by Agent (on 9. September 2022, 09:00) | 71 | 98 % |
| 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 % |
| 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 % |
| Negatively Constrained Slingshot Sudoku by stephane.bura (on 6. August 2020, 20:00) | 27 | 93 % |
| Red and Blue by zetamath (on 19. February 2021, 18:41) | 44 | 96 % |
| Arrow Sudoku by PotatoHead21 (on 26. April 2021, 09:02) | 33 | 90 % |
| Fourteen Arrows by FryTheGuy (on 14. September 2021, 06:47) | 46 | 96 % |
| Pandemonium by Testarossa (on 19. September 2021, 11:11) | 19 | 95 % |
| Suguru Chaos Deconstruction: Anti Equites by crispy16 (on 14. May 2022, 02:25) | 62 | 98 % |
| Serpents in the Shadows by XeonRisq (on 13. May 2023, 05:00) | 16 | 91 % |
| Aquarium Fillomino by wooferzfg (on 4. September 2023, 19:58) | 27 | 100 % |
| Biloxi - a Beachcomber Sudoku by glum_hippo (on 23. November 2023, 02:00) | 23 | 98 % |
