(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 | |
|---|---|---|---|
 | Summation U-Bahn #3: Castle Wall by Agent (on 17. October 2023, 09:00) | 52 |  100 % |
| Megha-Tropiques by Xenonetix (on 14. February 2022, 21:00) | 31 | 95 % |
| Renrenbanban by DarthParadox (on 25. April 2023, 17:54) | 58 | 98 % |
| Fillomino Chaos Construction #2 by dennischen (on 7. June 2023, 18:15) | 46 | 97 % |
| Make Room by Jay Dyer (on 5. July 2023, 00:36) | 33 | 96 % |
| Double Loop Japanese Sums by Agent (on 26. February 2024, 09:00) | 35 | 96 % |
| Japanese Sums: Pentomi-ones by Niverio (on 27. February 2024, 00:58) | 22 | 92 % |
| Uncopyrightable Cavino by PrimeWeasel (on 5. September 2024, 22:48) | 34 | 100 % |
| absolute annihilation by aqjhs (on 6. December 2024, 06:12) | 41 | 94 % |
| Hotel California by fjam (on 2. April 2025, 21:51) | 23 | 96 % |
| Wanddeko by Myxo (on 8. October 2025, 17:39) | 46 | 92 % |
| JS-Bahn (Japanese Summation U-Bahn) by cyddrdrd (on 1. November 2025, 00:00) | 24 | 96 % |
| Sudokuvania: Digits of Despair (v1.1.1) by SkepticalMario (on 4. April 2025, 02:27) | 355 | 100 % |
| Dynamic Construction by Niverio (on 6. April 2022, 00:26) | 43 | 99 % |
| Colossal Tapa and Chaos (ft. KNT) by wooferzfg (on 6. May 2023, 06:00) | 45 | 100 % |
| Soap Opera by Jay Dyer (on 28. January 2024, 21:19) | 41 | 92 % |
| Digital Loop by mathpesto (on 22. May 2025, 22:44) | 50 | 96 % |
| Pompeii by Kafkapharnaum (on 25. October 2025, 23:10) | 48 | 99 % |
| Eine Runde Inselhopping mit Höhlentour by tuace (on 29. July 2014, 08:30) | 27 | 98 % |
| Pentomino Sudoku by KNT (on 11. June 2022, 17:22) | 47 | 97 % |
