(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 | |
|---|---|---|---|
 | Sudon'tku by IsaacR (on 19. November 2021, 06:52) | 26 |  90 % |
| Exactly Eighty by krangune (on 23. January 2022, 17:08) | 47 | 97 % |
| Silvester by PulverizingPancake (on 24. January 2022, 02:00) | 38 | 98 % |
| Uneven Terrain (Parity Cave Sudoku) by Nordy (on 29. January 2022, 20:15) | 19 | 93 % |
| Frak by zetamath (on 20. February 2022, 21:09) | 65 | 98 % |
| Chaos Construction: Color Mixing by KNT (on 15. May 2022, 17:41) | 35 | 97 % |
| Deep sea weirdity (Between lines sudoku) by Lizzy01 (on 15. June 2022, 22:38) | 24 | 97 % |
| Quadratum by Xenonetix (on 23. July 2022, 22:22) | 47 | 99 % |
| Three Kings Go Horse Riding by Scruffamudda (on 15. August 2022, 02:19) | 15 | 92 % |
| Chaos Construction: X-Sums with Doublers by KNT (on 30. August 2022, 22:01) | 66 | 100 % |
| Benefactors by Andrewsarchus (on 10. September 2022, 07:31) | 17 | 98 % |
| Quantum-safe sudoku by chameleon (on 26. September 2022, 20:11) | 30 | 92 % |
| In Between the Spaces by XeonRisq (on 12. October 2022, 04:00) | 33 | 94 % |
| Disam Bonkers by ICHTUES (on 1. January 2023, 06:00) | 17 | 97 % |
| Santa Puzzle - for dumediat by the_cogito (on 9. January 2023, 18:01) | 28 | 95 % |
| Prison Party of Eight by lepton (on 10. January 2023, 18:59) | 18 | 93 % |
| Tachyons and Black Holes (Black Hole #1) by heliopolix (on 16. January 2023, 20:00) | 30 | 95 % |
| Made to be Broken by jwsinclair (on 23. January 2023, 20:54) | 36 | 96 % |
| Nurikabe and Chaos by wooferzfg (on 20. February 2023, 02:53) | 60 | 100 % |
| Breakthrough by Xenonetix (on 3. March 2023, 03:03) | 61 | 98 % |
