(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 | |
|---|---|---|---|
 | Treasure Box (Entropy Killer) by Mad-Tyas (on 26. February 2024, 18:19) | 43 |  91 % |
| Tetris Sum Line by Chad (on 2. March 2024, 00:51) | 26 | 98 % |
| Cosmogony by Kafkapharnaum (on 25. March 2024, 17:31) | 29 | 99 % |
| Doubler Trickery by Mad-Tyas (on 12. October 2024, 12:33) | 13 | 92 % |
| Dismay (Region Sum Lines Sudoku) by Qodec (on 29. June 2022, 22:50) | 68 | 97 % |
| Disconnection by fritzdis (on 12. January 2023, 13:43) | 54 | 96 % |
| Highway to the Danger Zone by Jay Dyer (on 23. May 2023, 21:52) | 55 | 93 % |
| The Usurper by KMD (on 15. April 2024, 02:09) | 51 | 96 % |
| Japanische Arithmetik II by tuace (on 25. June 2014, 17:30) | 37 | 99 % |
| Twin Rooms (Chaos Construction) by Agent (on 14. June 2022, 09:00) | 41 | 98 % |
| Shade Your Own Puzzle: YinYang vs Sudoku #1 by Playmaker6174 (on 20. August 2024, 19:00) | 44 | 95 % |
| Knotted Arrows by antiknight (on 20. April 2022, 22:34) | 29 | 90 % |
| X (Chaos Construction) by tallcat (on 11. April 2024, 07:00) | 58 | 97 % |
| Yin Yang Sudoku Deconstruction [9x9] by Christounet (on 7. April 2024, 09:21) | 89 | 99 % |
| Party chaos by Lizzy01 (on 27. June 2024, 21:43) | 27 | 99 % |
| Japanese Ranking by KNT (on 11. June 2024, 21:18) | 52 | 99 % |
| Strange Loop by Andrewsarchus (on 28. September 2021, 16:33) | 42 | 99 % |
| Vampire Whispers by yttrio (on 19. May 2023, 15:27) | 20 | 100 % |
| Shuttle islands [Nurikabe U-Bahn Bridges 13x14] by Christounet (on 16. January 2024, 01:00) | 20 | 97 % |
| MGC-1326 [Masyu Star Battle] by Christounet (on 17. July 2024, 23:54) | 24 | 99 % |
