(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 | |
|---|---|---|---|
 | Sum Line Sudoku #2 by Phistomefel (on 8. October 2022, 12:57) | 115 |  98 % |
| Adventsportale, Teil 4 by pirx (on 23. December 2018, 12:00) | 47 | 96 % |
| Network by Niverio (on 15. February 2023, 16:20) | 73 | 97 % |
| Suguru Chaos Deconstruction #5: Region Sums by mathpesto (on 23. March 2022, 01:51) | 111 | 98 % |
| String Theory (Renban Incomplete Arrow) by tallcat (on 19. July 2021, 17:03) | 27 | 96 % |
| Crypto Japanese Cave-Bahn by KNT (on 18. January 2023, 07:32) | 51 | 98 % |
| Entropy Exhibition by Mad-Tyas (on 19. September 2023, 12:15) | 54 | 93 % |
| Shuttle islands [Nurikabe U-Bahn Bridges 13x14] by Christounet (on 16. January 2024, 01:00) | 26 | 96 % |
| Round totals reclining stucco deconstruction. (8, 7) by Oddlyeven (on 7. February 2024, 18:32) | 29 | 98 % |
| Oklahoma City by ICHTUES (on 27. November 2022, 06:00) | 68 | 96 % |
| Knapp Daneben Twin Killer Sudoku by Richard (on 24. April 2009, 10:56) | 82 | 94 % |
| Wanna Take This Outside? by ThePedallingPianist (on 21. December 2023, 01:09) | 89 | 98 % |
| Pitchfork Emporium by FryTheGuy (on 21. December 2021, 04:10) | 31 | 95 % |
| [N]ine [B]oxes by Gliperal (on 14. July 2022, 09:20) | 19 | 90 % |
| Abstract Art (Equalines, Entropy) by Mad-Tyas (on 27. February 2023, 09:16) | 37 | 97 % |
| Snack'O'Mino [Level #2] by Christounet (on 9. March 2023, 12:47) | 55 | 100 % |
| Chaos Construction: XY-Sums by ns08 (on 28. May 2023, 23:55) | 34 | 94 % |
| Crystallizer (Filloku #7) by mormagli (on 30. January 2024, 17:31) | 22 | 99 % |
| Foggy foggy x-sums by sanabas (on 26. July 2024, 07:36) | 49 | 94 % |
| Chocona Mall by Jay Dyer (on 16. August 2024, 21:19) | 23 | 93 % |
