(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) | 50 |  98 % |
| Disjunction Function by Jay Dyer (on 30. April 2024, 23:20) | 113 | 98 % |
| Japanese Sums #4: Pinpoint by Myxo (on 5. October 2023, 10:49) | 55 | 98 % |
| X-clusivity by Jay Dyer (on 9. August 2023, 22:15) | 112 | 97 % |
| clover's expert math class by Qodec (on 13. July 2021, 23:09) | 52 | 99 % |
| Xs and Os [Parity, Whispers, Palindromes] by Malrog (on 5. December 2022, 01:42) | 50 | 98 % |
| Star Python 2 (Star Battle Snake Sudoku Hybrid) by peterchayward (on 16. March 2021, 18:56) | 57 | 99 % |
| Ein echtes Schachsudoku by CJK (on 23. August 2021, 15:39) | 66 | 98 % |
| Meanest Mini by chameleon (on 1. January 2024, 17:10) | 66 | 98 % |
| Splash by Joseph nehme (on 17. November 2022, 10:18) | 61 | 93 % |
| Pacify by SamuPiano (on 26. March 2024, 17:00) | 59 | 97 % |
| Round the Houses (Killer Loop) by tallcat (on 25. March 2023, 15:37) | 62 | 96 % |
| Chaos Construction: Miracle on 64 Cells by Playmaker6174 (on 18. January 2025, 00:00) | 58 | 99 % |
| Die Kryptos - S02E03: Japanische Summen / Abstände by tuace (on 16. March 2018, 15:10) | 61 | 100 % |
| Quilt by mnasti2 (on 17. May 2023, 14:45) | 63 | 96 % |
| Whispern't Loop by yttrio (on 6. July 2024, 02:04) | 62 | 96 % |
| Heated Chaos by yttrio (on 24. August 2024, 01:45) | 131 | 98 % |
| Dynamic Dots by Niverio (on 7. March 2022, 11:56) | 64 | 96 % |
| Square Dance by Jay Dyer (on 9. July 2024, 22:47) | 74 | 95 % |
| Te Ka (Nurikabe Chaos Construction) by MaizeGator (on 16. June 2024, 03:39) | 61 | 97 % |
