(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 | |
|---|---|---|---|
 | Field Lines by mathpesto (on 8. April 2023, 21:10) | 89 |  98 % |
| Cave 20x20 by Strosahl (on 8. December 2020, 20:54) | 31 | 97 % |
| Biagonal Bichael (Chaos Construction) by purpl (on 29. May 2022, 17:32) | 33 | 98 % |
| Sagitta (Anti-XV Arrow Sudoku) by Phistomefel (on 1. August 2022, 17:06) | 115 | 94 % |
| Wichtel 2018 (2): Schnorchelreise by wichtel (on 6. June 2019, 10:28) | 34 | 99 % |
| Enclosure by Xenonetix (on 21. September 2022, 01:11) | 37 | 100 % |
| Chaos Construction: Oenopion's Revenge by Niverio (on 3. July 2022, 10:13) | 78 | 99 % |
| Shading Sudoku Collection by KNT (on 10. August 2022, 05:09) | 39 | 100 % |
| Liar Japanese Sums #6 - Ciphered Tapa by Niverio (on 10. September 2023, 20:47) | 43 | 99 % |
| Elementary by Christounet (on 18. September 2023, 22:30) | 49 | 98 % |
| Supernova by Nahileon (on 3. November 2021, 20:32) | 64 | 99 % |
| Archers and Knights by SudokuExplorer (on 23. March 2021, 01:00) | 91 | 98 % |
| Chasm Construction by AFrayedKnot (on 23. May 2024, 22:35) | 103 | 98 % |
| Japanische Inseln, knapp daneben by pirx (on 19. October 2014, 17:30) | 48 | 99 % |
| Loses Kalenderblatt April 2019 (2/2) by April (on 1. April 2019, 12:00) | 23 | 99 % |
| Die Kryptos - S04E03: Roller Coaster by tuace (on 21. January 2020, 08:06) | 51 | 100 % |
| Locust [Kropki Killer Sudoku] by Panthera (on 12. December 2020, 13:00) | 29 | 93 % |
| . o T o . by Lisztes (on 30. June 2021, 01:00) | 19 | 92 % |
| Ten Knights by FryTheGuy (on 20. August 2021, 08:16) | 121 | 97 % |
| Chicago by ICHTUES (on 29. August 2021, 06:00) | 31 | 97 % |
