(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 | |
|---|---|---|---|
 | Japanische Krypto-Summen gratulieren by pin7guin (on 9. July 2016, 00:00) | 57 |  98 % |
| Heatmap Sudoku by Jesper (on 13. June 2020, 16:19) | 42 | 97 % |
| Double Stacks by bboom (on 24. May 2025, 14:46) | 28 | 93 % |
| The Maltese Zipper by Oddlyeven (on 31. December 2023, 16:06) | 48 | 96 % |
| Zahlenbild-Rundweg by Calavera (on 22. June 2009, 16:07) | 129 | 96 % |
| Christmas Cat Run by phil_the (on 2. January 2025, 14:25) | 37 | 94 % |
| Dutch Flat Mates (Japanese Sums) by Flinty (on 9. October 2024, 11:30) | 91 | 92 % |
