(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 | |
|---|---|---|---|
 | Numbered Regions X-Sums (9x9 Chaos Construction) by ONeill (on 24. November 2022, 22:58) | 53 |  98 % |
| Star Python 2 (Star Battle Snake Sudoku Hybrid) by peterchayward (on 16. March 2021, 18:56) | 58 | 99 % |
| Ein echtes Schachsudoku by CJK (on 23. August 2021, 15:39) | 67 | 97 % |
| Border Square Sums by Phistomefel (on 15. March 2024, 05:49) | 123 | 98 % |
| Summer Snakes by yttrio (on 25. August 2023, 22:28) | 64 | 97 % |
| Not All Who Wander Are Lost by Allagem (on 4. August 2025, 13:29) | 62 | 94 % |
| Die Kryptos - S02E03: Japanische Summen / Abstände by tuace (on 16. March 2018, 15:10) | 62 | 100 % |
| Ulte Nus Plura (Suguru Chaos Deconstruction) by crispy16 (on 2. May 2022, 15:57) | 65 | 99 % |
| Fillomino U-Bahn by KNT (on 1. May 2023, 23:28) | 64 | 100 % |
| Dynamic Dots by Niverio (on 7. March 2022, 11:56) | 67 | 96 % |
| Mounted Archery by Joseph nehme (on 29. January 2022, 08:10) | 77 | 90 % |
| Triptych by Oddlyeven (on 16. July 2025, 16:47) | 62 | 95 % |
| MasyU-Bahn (Teil 3) by Zzzyxas (on 2. April 2015, 20:35) | 64 | 99 % |
| HalfYin-TwoYang by DJV (on 11. January 2023, 15:37) | 77 | 94 % |
| Zipper Zipper by antiknight (on 20. December 2023, 03:32) | 74 | 97 % |
| Equal Sudoku II by Realshaggy (on 29. April 2013, 12:23) | 74 | 94 % |
| Dandelion (Anti-Knight Thermo Sudoku) by Phistomefel (on 7. June 2022, 02:45) | 176 | 97 % |
| Chaos FilloSudokumino by MagnusJosefsson (on 14. September 2022, 15:00) | 155 | 98 % |
| Heated Chaos by yttrio (on 24. August 2024, 01:45) | 165 | 98 % |
| Chaos Construction: Corridors by vidarino (on 1. January 2022, 14:24) | 77 | 96 % |
