(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 | |
|---|---|---|---|
 | Equal Color Sums by rmahus (on 6. January 2022, 08:00) | 20 |  92 % |
| Hex 2: Regular Hexagons, Irregular Sudoku by mathpesto (on 8. June 2022, 22:53) | 21 | 94 % |
| Rope Skipping by Mad-Tyas (on 6. December 2022, 05:32) | 19 | 92 % |
| Until Ten (10-lines, parity mirror) by the_cogito (on 20. February 2023, 15:28) | 39 | 97 % |
| Thermo Sudoku by Jeet Sampat (on 17. February 2024, 18:21) | 19 | 90 % |
| Chroma-Some (Killer) by zegres (on 5. March 2024, 05:31) | 42 | 90 % |
| Four Corner Shots by noswald (on 25. May 2024, 18:28) | 42 | 95 % |
| Kurotto (Aqre) by KNT (on 3. June 2024, 15:44) | 88 | 98 % |
| Loopy Whisper X-Sums by yttrio (on 8. June 2024, 04:31) | 76 | 98 % |
| Dutch Flat Mates (Chaos Construction Shifter) - Palpot Collab by Flinty (on 16. October 2024, 11:30) | 49 | 96 % |
| Zodiac Project: Ponta Delgada by Florian Wortmann (on 9. July 2024, 19:49) | 78 | 97 % |
| U-Bahn (1) by KNT (on 15. April 2023, 06:02) | 56 | 96 % |
| Take More U-Turns by Black_Doom (on 30. June 2024, 18:39) | 56 | 96 % |
| Quad sums sudoku by udukos (on 17. August 2021, 18:07) | 46 | 95 % |
| Double Duty | Zweifache Zahlenbedeutung by olima (on 21. February 2023, 22:52) | 46 | 98 % |
| Take U-Turns by Black_Doom (on 20. March 2024, 04:35) | 46 | 96 % |
| Discontinuity? by JayForty (on 2. February 2024, 16:38) | 84 | 96 % |
| Rumors (German Whispers) by tallcat (on 8. October 2021, 17:02) | 149 | 98 % |
| Factor Map by ul-Rhymm (on 30. June 2024, 14:57) | 40 | 99 % |
| Water From A Stone by Biscuit (on 26. August 2024, 18:07) | 37 | 91 % |
