(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 | |
|---|---|---|---|
 | Pencil puzzle sudoku hybrid series #5 - Slitherlink killer sudoku by Aspartagcus (on 9. January 2021, 14:48) | 32 |  96 % |
| Les Flèches by Joseph nehme (on 15. May 2021, 07:16) | 28 | 90 % |
| The 4-Colour Theorem by starwarigami (on 5. February 2023, 10:00) | 78 | 96 % |
| Rule of Thirds by sfushidahardy (on 15. October 2025, 17:19) | 30 | 100 % |
| Chaos Construction: Killer Cages by KNT (on 4. April 2022, 23:31) | 130 | 96 % |
| Proximity (Renban/Antiknight) by dumediat (on 13. May 2023, 14:29) | 74 | 93 % |
| Adventskalender 2023, Türchen 16 - Untergrundangeln by Zzzyxas (on 16. December 2023, 07:00) | 33 | 98 % |
| Sandwich Product by Prof.Dori (on 5. July 2024, 09:28) | 37 | 95 % |
| XY-Differences III by glum_hippo (on 14. July 2020, 02:12) | 50 | 91 % |
| The Snake Nest by matt383 (on 9. October 2020, 14:03) | 40 | 98 % |
| The Corners Are Even - Arrow Odd/Even Sudoku by Mr.Menace (on 2. February 2022, 23:04) | 39 | 96 % |
| Quincies by lerroyy (on 11. June 2023, 19:14) | 39 | 92 % |
| Nothing to see here by fritzdis (on 31. August 2023, 09:36) | 35 | 98 % |
| A Little Mouthful (Short Sandwiches Sudoku) by Qodec (on 17. January 2025, 23:01) | 37 | 95 % |
| Lines Lines by SSG (on 17. September 2025, 07:05) | 41 | 93 % |
| Chained Killer Sudoku by Shinya (on 12. January 2020, 23:22) | 45 | 93 % |
| Killer Sudoku - Dirty Tricks by DiMono (on 25. November 2020, 16:27) | 51 | 97 % |
| Nexus by udukos (on 12. June 2021, 01:00) | 47 | 98 % |
| Fill-a-Renban by SSG (on 23. July 2023, 07:22) | 43 | 95 % |
| Chaos Construction by Phistomefel (on 21. April 2020, 00:27) | 165 | 97 % |
