(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 | |
|---|---|---|---|
 | Sandwiched in Between by udukos (on 16. January 2021, 05:37) | 29 |  99 % |
| Squiggle by Lisztes (on 11. April 2021, 01:00) | 31 | 96 % |
| Six-pack Linked Sudokus #3 by Genomico (on 25. February 2021, 03:49) | 47 | 92 % |
| Killer Sudoku by abed hawila (on 30. March 2021, 12:58) | 46 | 94 % |
| 7 (Arrow X Sudoku) by ICHTUES (on 25. April 2021, 06:00) | 40 | 93 % |
| Decidoku by Innocuous (on 18. August 2021, 01:31) | 18 | 95 % |
| Dance Partners / Die Tanzpartner by Auul (on 13. September 2021, 07:44) | 12 | 93 % |
| Framed Bats by Emphyrio (on 2. October 2021, 18:53) | 25 | 95 % |
| The X Days of 12-Mas by Mojo872 (on 1. December 2021, 16:49) | 20 | 90 % |
| Alphanumeric by jwsinclair (on 15. December 2021, 20:24) | 18 | 98 % |
| Antiknight Whispers by thoughtbyte (on 12. February 2022, 08:58) | 36 | 91 % |
| Unum Singulis by Eclectic_Hoosier (on 6. April 2022, 00:46) | 20 | 92 % |
| Alien Cube by Nahileon (on 23. March 2022, 17:36) | 34 | 96 % |
| ThanX (Sudoku25) by Sumanta(ANU) (on 4. May 2022, 14:27) | 27 | 90 % |
| Odd Turtle Sudoku by Thorsby (on 10. June 2022, 05:02) | 18 | 98 % |
| Watched (Run-on Renbans) by riffclown (on 12. September 2022, 00:18) | 41 | 98 % |
| The Butterfly - (Region Sum/Renban Lines) by Ennead (on 12. September 2022, 20:51) | 14 | 93 % |
| The Cs by ademjaz (on 23. September 2022, 00:54) | 35 | 93 % |
| Chaos Constriction (6x6) by Nordy (on 4. October 2022, 00:34) | 17 | 90 % |
| Kropki a-lien by chameleon (on 15. October 2022, 02:59) | 17 | 93 % |
