(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 | |
|---|---|---|---|
 | Roller Coaster Yin Yang Cipher by Piatato (on 26. December 2022, 11:26) | 33 |  100 % |
| Unique Japanese Sum Sudoku by tesseralis (on 28. July 2023, 05:34) | 84 | 97 % |
| Summation U-Bahn #6: Liar by Agent (on 30. November 2024, 09:00) | 34 | 100 % |
| Ʈɦᶒ Horoloɠᶖᶙḿ by ViKingPrime (on 2. August 2025, 00:00) | 19 | 100 % |
| Japanese Minesweeper (Intermediate) by cyddrdrd (on 28. March 2026, 00:00) | 22 | 100 % |
| Runway (Killer sudoku with maximum totals + arrows) by Qodec (on 6. October 2024, 19:06) | 83 | 95 % |
| The S-Cell Miracle by Niverio (on 22. May 2022, 16:40) | 58 | 97 % |
| Japanese Icewalk (2) by KNT (on 21. August 2025, 00:48) | 36 | 92 % |
| Crux by Jay Dyer (on 22. October 2023, 16:09) | 92 | 97 % |
| Chaos Construction: Increasing Path by KNT (on 3. October 2022, 23:31) | 108 | 96 % |
| Not One Black Dot by mormagli (on 11. February 2023, 04:50) | 20 | 95 % |
| Manifold Paths (Advanced Black Hole) by heliopolix (on 16. June 2023, 02:14) | 19 | 100 % |
| Mini-Colossal Octoquadri II: U-Bahn by sfushidahardy (on 20. March 2025, 02:53) | 19 | 100 % |
| The Graveyard Of Emptiness by fjam (on 10. October 2025, 20:02) | 67 | 94 % |
| Invisible Thermometers by Nahileon (on 17. May 2023, 12:51) | 53 | 94 % |
| Außerirdische Krypto Killer Pyramide by tuace (on 30. April 2014, 20:00) | 32 | 96 % |
| Quite a Mouthful by Gliperal (on 2. January 2021, 23:49) | 31 | 96 % |
| 4D Killer Sudoku by FryTheGuy (on 11. October 2021, 22:29) | 31 | 100 % |
| Japanese Forest Walk (2) by KNT (on 13. November 2025, 15:18) | 36 | 98 % |
| Chaos Construction : Wrogn by lerroyy (on 8. June 2022, 20:59) | 73 | 98 % |
