(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 | |
|---|---|---|---|
 | Pandemonium by Testarossa (on 19. September 2021, 11:11) | 18 |  95 % |
| Valiant Viper in the King's Garden (Chess Snake Sudoku) by Nordy (on 5. April 2022, 01:20) | 29 | 95 % |
| Stepwell by mormagli (on 14. May 2022, 07:17) | 18 | 94 % |
| Chaos Construction: diagonals by Prutsbeest (on 23. May 2022, 07:00) | 32 | 97 % |
| The 2-Colour Theorem by starwarigami (on 17. February 2023, 08:46) | 63 | 94 % |
| Some Thermo Nonsense by LittleNightmaresLady (on 14. April 2023, 18:15) | 15 | 92 % |
| Serpents in the Shadows by XeonRisq (on 13. May 2023, 05:00) | 15 | 90 % |
| Norinori Killer Sudoku by SudokuExplorer (on 9. February 2021, 01:00) | 80 | 96 % |
| Messier 43 (Galaxy Region Sum Lines) by purpl (on 1. October 2022, 01:31) | 61 | 99 % |
| Rätselhausen - cinque relazioni by Statistica (on 1. December 2017, 23:55) | 34 | 97 % |
| 159 Sandwiches by RockyRoer (on 19. February 2021, 21:33) | 33 | 99 % |
| Rigel (Arrow Sudoku) by emmettcito (on 27. April 2021, 17:01) | 38 | 98 % |
| Missing Quads by antiknight (on 28. June 2022, 19:05) | 38 | 93 % |
| Ready For Launch by Niverio (on 7. May 2024, 10:19) | 40 | 95 % |
| Summenbild mit Lücken by Calavera (on 1. September 2009, 02:51) | 67 | 96 % |
| Cave Fillomino #1 (10x10) by Jesper (on 29. August 2020, 11:40) | 68 | 100 % |
| Vacancy (Chaos Construction) by thoughtbyte (on 28. August 2023, 06:30) | 72 | 96 % |
| Min-Max-Sichtblöcke (3) by BFaw (on 14. December 2016, 10:00) | 18 | 95 % |
| Wichtel 2017 (4): Drei Wichtel und 144 Häuser by wichtel (on 26. May 2018, 07:04) | 36 | 99 % |
| Ginnels & Snickets (Between Skyscraper) by tallcat (on 29. September 2022, 19:22) | 55 | 98 % |
