(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 | |
|---|---|---|---|
 | "Incomplete" Killer Sudoku by Greg (on 12. June 2020, 01:55) | 25 |  90 % |
| Battlefield Sudoku - Ring Theory by DiMono (on 4. July 2020, 23:21) | 31 | 90 % |
| Yajilin Sudoku by Madmahogany (on 19. July 2020, 12:39) | 35 | 94 % |
| Whodunit by Djmelee3000 (on 11. August 2020, 00:56) | 27 | 93 % |
| Defending Digits (Castle Sudoku) by Mark Sweep (on 14. October 2020, 12:26) | 27 | 96 % |
| Pentomino Loop Sudoku by Quarterthru (on 5. November 2020, 12:00) | 28 | 94 % |
| 9 Cages by PrimeWeasel (on 30. November 2020, 15:57) | 25 | 90 % |
| The Key by jetalix (on 8. January 2021, 20:02) | 28 | 98 % |
| X-Sums Fillomino #3 (4x4x4) by Jesper (on 15. March 2021, 19:53) | 40 | 100 % |
| Revenge of the Hash (Irregular Thermo Sudoku) by lavaloid (on 9. May 2021, 11:00) | 14 | 92 % |
| Even Hunter by Lisztes (on 16. October 2021, 01:00) | 22 | 92 % |
| 159 Shards by Qodec (on 22. September 2021, 12:36) | 86 | 93 % |
| Key Word (feat. Playmaker6174) by purpl (on 19. October 2021, 17:45) | 19 | 97 % |
| Campfire by Nahileon (on 12. January 2022, 21:24) | 54 | 97 % |
| Line of Sight Chaos Production by RockyRoer (on 29. January 2022, 03:39) | 65 | 99 % |
| X-Sums: 37 by the_cogito (on 1. February 2022, 16:58) | 13 | 98 % |
| Transfer by Emphyrio (on 15. March 2022, 03:06) | 44 | 97 % |
| Knuckle O'Sandwich by zegres (on 13. April 2022, 06:33) | 35 | 96 % |
| Kropki-cycle by tesseralis (on 28. July 2022, 12:58) | 19 | 100 % |
| Wichtel 2021 (11): Eine neue Route durch das schöne Rätselhausen by wichtel (on 22. November 2022, 10:22) | 12 | 100 % |
