(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 | |
|---|---|---|---|
 | Same Old Same Old by MathGuy_12 (on 18. July 2025, 23:23) | 50 |  98 % |
| Fünf aßen Neun by MavericksJD (on 30. January 2022, 19:53) | 30 | 95 % |
| Where did the king go? by Jagga (on 20. August 2022, 16:04) | 28 | 91 % |
| Roman Hieroglyph by lepton (on 17. January 2023, 17:20) | 27 | 97 % |
| 2 Corinthians 4:18 (Aqre Anti-X-Sum Chaos Deconstruction) by MaizeGator (on 18. September 2024, 01:43) | 29 | 95 % |
| hello DubiousMobius by aqjhs (on 5. July 2025, 00:00) | 30 | 97 % |
| Elementary by Christounet (on 18. September 2023, 22:30) | 54 | 98 % |
| Cave 20x20 by Strosahl (on 8. December 2020, 20:54) | 32 | 97 % |
| Quantum-safe sudoku by chameleon (on 26. September 2022, 20:11) | 31 | 91 % |
| Matty Didn't Call You Back Because He Had The Wrogn Number by Laake (on 26. September 2024, 22:11) | 94 | 96 % |
| Arcade (Pentopia + Simple Loop) by sfushidahardy (on 17. November 2024, 01:03) | 33 | 97 % |
| Verspäteter Geburtstagsgruß aus dem All by ibag (on 27. June 2019, 00:00) | 30 | 99 % |
| Neural Network by Xenonetix (on 26. November 2022, 14:41) | 39 | 96 % |
| Chaos Construction: X-Sums with Doublers by KNT (on 30. August 2022, 22:01) | 72 | 97 % |
| Dancing Like Butterfly Wings by dennischen (on 31. December 2024, 02:28) | 47 | 96 % |
| Chaos Construction: Oenopion's Revenge by Niverio (on 3. July 2022, 10:13) | 83 | 99 % |
| Chaos Deconstruction: Cave by KNT (on 6. July 2022, 07:57) | 79 | 96 % |
| Disjoint group little killer sudoku X by Lizzy01 (on 4. March 2021, 21:40) | 45 | 99 % |
| Shading Sudoku Collection by KNT (on 10. August 2022, 05:09) | 42 | 97 % |
| Japanische Inseln, knapp daneben by pirx (on 19. October 2014, 17:30) | 50 | 99 % |
