(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 | |
|---|---|---|---|
 | Top Right Boi by DubiousMobius (on 21. June 2025, 12:00) | 57 |  100 % |
| Oklahoma City by ICHTUES (on 27. November 2022, 06:00) | 67 | 96 % |
| Sum Line Sudoku #2 by Phistomefel (on 8. October 2022, 12:57) | 110 | 98 % |
| Wanna Take This Outside? by ThePedallingPianist (on 21. December 2023, 01:09) | 81 | 100 % |
| Colossal Slitherlink Sudoku by Agent (on 5. September 2023, 09:00) | 49 | 99 % |
| Network by Niverio (on 15. February 2023, 16:20) | 71 | 96 % |
| Knapp Daneben Twin Killer Sudoku by Richard (on 24. April 2009, 10:56) | 80 | 94 % |
| Abstract Art (Equalines, Entropy) by Mad-Tyas (on 27. February 2023, 09:16) | 36 | 97 % |
| Chaos Construction: XY-Sums by ns08 (on 28. May 2023, 23:55) | 33 | 94 % |
| 247, 368... by twototenth (on 26. September 2023, 08:00) | 21 | 92 % |
| 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) | 44 | 94 % |
| Summation U-Bahn #5: Sorted Clues by Agent (on 22. October 2024, 09:00) | 29 | 96 % |
| Urban Madness (Chaos Construction) by Mad-Tyas (on 23. August 2025, 05:05) | 22 | 93 % |
| Zag by grkles (on 18. March 2021, 11:46) | 46 | 98 % |
| The Turtle (Renban, Entropy) by Mad-Tyas (on 28. March 2023, 09:21) | 38 | 98 % |
| Japanese Sums Narrow Cave Cipher: Mirrors (11x11) by Jesper (on 2. June 2023, 16:04) | 35 | 100 % |
| A Rose by PotatoHead21 (on 2. August 2023, 08:24) | 35 | 95 % |
| Knights Mate by blackjackfitz (on 17. January 2024, 20:52) | 43 | 95 % |
| Second Rodeo (collab. with Tallcat) by jwsinclair (on 17. October 2024, 23:06) | 65 | 98 % |
