(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 | |
|---|---|---|---|
 | Millstone by jwsinclair (on 13. June 2024, 20:59) | 77 |  98 % |
| Killers and Palindromes by tenaliraman (on 3. January 2021, 06:45) | 38 | 98 % |
| Building Blocks by grkles (on 2. February 2022, 04:00) | 34 | 97 % |
| All Directions by Joseph nehme (on 19. February 2022, 07:48) | 33 | 97 % |
| Kropki Magnetplatten III by tuace (on 12. January 2014, 07:30) | 31 | 99 % |
| Dubai by Jay Dyer (on 7. March 2023, 22:49) | 35 | 94 % |
| E ∩ tropy (Killer, Entropy Theme) by Crusader175 (on 20. May 2023, 16:00) | 34 | 94 % |
| Half Full Jar by Nimo (on 25. February 2025, 10:47) | 34 | 95 % |
| Little Killer by Strosahl (on 7. April 2021, 05:36) | 31 | 99 % |
| Adventskalender 2023, Türchen 15 - Knapp daneben U-Bahn by Zzzyxas (on 15. December 2023, 07:00) | 29 | 94 % |
| Cosmic Cages by yanggang (on 24. July 2024, 23:20) | 30 | 93 % |
| 4-color killer sudoku #2 by Nylimb (on 3. April 2021, 04:45) | 56 | 100 % |
| arROw SudOkU by filuta (on 1. March 2021, 18:08) | 27 | 90 % |
| Houston by ICHTUES (on 5. September 2021, 06:00) | 25 | 92 % |
| Feeling Six Yet? by oskode (on 27. August 2025, 06:06) | 27 | 93 % |
| Pentomino Schleifen (NFF) by Richard (on 8. October 2010, 12:00) | 28 | 92 % |
| Palindrome Madness by SirWoezel (on 2. June 2020, 18:26) | 25 | 94 % |
| Killocator by starwarigami (on 27. October 2021, 10:15) | 56 | 98 % |
| Rising Arrow Sudoku - Halloween Crab by DiMono (on 3. June 2021, 18:26) | 54 | 97 % |
| How Bizarre by Nahileon (on 5. June 2024, 14:42) | 44 | 95 % |
