(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 | |
|---|---|---|---|
 | Juosan Parity Parade by kolot (on 9. November 2021, 13:31) | 19 |  99 % |
| Sum-thing's Wrogn by Jay Dyer (on 5. February 2022, 13:43) | 21 | 99 % |
| Fireworks and Firecrackers by Emphyrio (on 20. March 2022, 01:15) | 23 | 94 % |
| Circle of Fifths by Cephalo (on 28. April 2022, 19:40) | 42 | 95 % |
| Time to Color by EricRathbun (on 16. October 2022, 21:17) | 21 | 93 % |
| Castle Woku (Castle Wall/Sudoku) by Wessel Strijkstra (on 16. December 2022, 16:49) | 39 | 99 % |
| Disturbed Balance by lepton (on 19. December 2022, 20:35) | 27 | 99 % |
| Difference by mormagli (on 4. March 2023, 05:59) | 19 | 97 % |
| Parity Loop #2: Irregular by Paletron (on 5. September 2023, 11:10) | 18 | 98 % |
| Filloku by mormagli (on 8. September 2023, 20:38) | 22 | 96 % |
| Ƨ Slithering Loop Ƨ by ElChiglia (on 14. October 2023, 08:05) | 46 | 92 % |
| H-Bomb by Abdul the Killer (on 30. April 2024, 12:34) | 44 | 91 % |
| Can You Count the Whispers? by Tobias Brixner (on 26. May 2024, 16:07) | 48 | 96 % |
| Friendly Mean Thermo by Prof.Dori (on 12. August 2024, 19:21) | 15 | 94 % |
| Trapped by mathpesto (on 25. August 2024, 05:18) | 37 | 91 % |
| Activated Cage Totals by RockyRoer (on 8. November 2024, 14:41) | 16 | 92 % |
| Q-Bahn (U-Bahn Octoquadri) by the_cogito (on 9. May 2025, 20:12) | 28 | 100 % |
| Picking Blackcurrants by Kaktuslav (on 27. September 2025, 08:00) | 47 | 99 % |
| Pentominous Killer Kakuro by Agent (on 10. February 2024, 09:00) | 105 | 99 % |
| Killer of the Seas by Piatato (on 9. June 2021, 13:57) | 63 | 99 % |
