(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 | |
|---|---|---|---|
 | Going in Circles by antiknight (on 1. December 2022, 15:06) | 47 |  95 % |
| Made to be Broken by jwsinclair (on 23. January 2023, 20:54) | 43 | 96 % |
| Messier 43 (Galaxy Region Sum Lines) by purpl (on 1. October 2022, 01:31) | 63 | 99 % |
| Cageless (X) Killer Sudoku no. 2 by Shinya (on 23. March 2020, 12:58) | 23 | 95 % |
| Japanese Anti Knight Double 2358 Sums by pandiani42 (on 28. June 2020, 17:21) | 22 | 90 % |
| CTC Tribute Arrow Sudoku by Lizzy01 (on 6. June 2021, 20:37) | 27 | 95 % |
| Broken Square by PotatoHead21 (on 14. August 2021, 08:24) | 22 | 99 % |
| DEATH (collaboration) by grkles (on 4. January 2022, 22:20) | 44 | 99 % |
| Activated Japanese Sums by RockyRoer (on 12. November 2022, 13:36) | 21 | 95 % |
| Pandora's Renban by JeffWajes (on 18. January 2023, 21:12) | 49 | 97 % |
| The Chained Trio (Between x Lockout x Double Arrow) by Playmaker6174 (on 19. March 2023, 18:23) | 26 | 96 % |
| FMTC by Starstorm (on 20. June 2023, 21:21) | 22 | 92 % |
| Arrow Jungle by PotatoHead21 (on 18. August 2023, 11:49) | 24 | 93 % |
| Yin-Yang Renbanominos 1 by Die Hard (on 29. April 2024, 07:56) | 25 | 92 % |
| The Fillomino Frog by Die Hard (on 7. January 2025, 10:49) | 25 | 97 % |
| A-Row & Z-Row by Scojo (on 25. October 2025, 02:22) | 22 | 99 % |
| Zodiac Project: Astrolabe by Sotehr (on 30. October 2025, 00:00) | 51 | 98 % |
| Thirteen Ghosts by mathpesto (on 19. September 2024, 22:37) | 74 | 98 % |
| 10-in-9 killer sudoku #3 by Nylimb (on 11. February 2020, 22:35) | 46 | 99 % |
| Antiknight Killer Sudoku by PotatoHead21 (on 15. September 2021, 05:20) | 98 | 99 % |
