(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 | |
|---|---|---|---|
 | Skyscraper Aquarium Sudoku by Sam Knott (on 23. June 2020, 18:01) | 31 |  96 % |
| Wichtel 2019 (10): Die Wohnquartiere der Wichtel by wichtel (on 2. November 2020, 19:20) | 47 | 100 % |
| 10-in-9 CLXVI sudoku by Nylimb (on 21. October 2020, 20:10) | 15 | 94 % |
| Asterisk (palindrome killer sudoku x) by clover (on 23. November 2020, 16:01) | 84 | 94 % |
| Odd/Even Consecutive Killer 4 by Quarterthru (on 9. January 2021, 12:00) | 23 | 94 % |
| Primality Party by abed hawila (on 12. March 2021, 15:44) | 13 | 96 % |
| XY-Differences and -Sums by glum_hippo (on 30. April 2021, 06:00) | 17 | 98 % |
| 6x6 Chaos Construction: Boundary N-Sums (墨子) by SudokuExplorer (on 27. April 2021, 01:00) | 27 | 94 % |
| Jigsaw by PotatoHead21 (on 20. June 2021, 19:54) | 20 | 92 % |
| Two's Company by apiyo (on 11. September 2021, 05:52) | 15 | 94 % |
| Minesweeper Sudoku by Niverio (on 24. November 2021, 23:53) | 40 | 98 % |
| Classic-style Killer Sudoku by Jeet Sampat (on 27. January 2022, 22:59) | 28 | 94 % |
| The Andromeda Chain (Spiral Galaxies, Lockout Lines) by Chilly (on 8. February 2022, 16:08) | 13 | 98 % |
| Polychromatic by oklux (on 28. March 2022, 20:32) | 22 | 97 % |
| Gossip Circle by mormagli (on 5. June 2022, 23:52) | 40 | 98 % |
| The Grand Design (Numbered Room combo) by Playmaker6174 (on 27. July 2022, 05:54) | 21 | 94 % |
| Cliques by purpl (on 22. August 2022, 22:40) | 23 | 92 % |
| Ringworms by XeonRisq (on 8. September 2022, 05:00) | 34 | 92 % |
| Yin Yang Arrows by Schwupel (on 23. September 2022, 19:36) | 127 | 99 % |
| Tuning Forks #3 by Blashyrkh (on 28. March 2023, 12:09) | 23 | 93 % |
