(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 | |
|---|---|---|---|
 | U-Bahn with Cages by wooferzfg (on 26. April 2023, 23:39) | 36 |  95 % |
| Vlad the Impaler - Parity mirror, killer sudoku by Mr.Menace (on 19. August 2023, 08:14) | 41 | 94 % |
| N-lines by Lizzy01 (on 19. February 2024, 11:19) | 19 | 95 % |
| Tail of the Okapi by glum_hippo (on 22. December 2025, 20:41) | 15 | 97 % |
| War with Pythagoras by JeffWajes (on 20. July 2025, 11:39) | 88 | 96 % |
| Smus-X by Qodec (on 25. September 2022, 14:44) | 64 | 96 % |
| Guillotine by Qodec (on 4. September 2022, 12:20) | 53 | 95 % |
| This + This = That by EricRathbun (on 1. November 2023, 15:55) | 49 | 97 % |
| Edelweiß by loerting (on 27. December 2023, 23:20) | 56 | 95 % |
| Walking around town (Deconstruction) by Oripy (on 12. May 2025, 12:00) | 47 | 96 % |
| 4th of July Encrypted Thermo-Sandwich by Alexander Rappa (on 3. July 2020, 16:15) | 31 | 92 % |
| Killer Wasp by Quarterthru (on 31. May 2021, 12:00) | 31 | 97 % |
| Arrows and a Big X by GBPack (on 17. June 2021, 17:11) | 29 | 97 % |
| Stacked - Arrow Sudoku by Mr.Menace (on 6. July 2021, 20:51) | 49 | 97 % |
| Multiple Signs by tesseralis (on 9. June 2022, 01:20) | 32 | 97 % |
| Room Service by Xenonetix (on 9. October 2022, 02:02) | 27 | 93 % |
| Distinctiveness by Ridhwan (on 12. February 2024, 00:05) | 26 | 92 % |
| Echoing Cages by graggle (on 26. April 2025, 11:00) | 60 | 96 % |
| Japanische Hochhaus-Summen (Mini-Krypto) by ibag (on 21. September 2012, 22:04) | 56 | 98 % |
| 159 German Whispers Sudoku by Qodec (on 19. November 2021, 18:19) | 101 | 97 % |
