(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 | |
|---|---|---|---|
 | Sudoku Variants Series (224) - Sum or Product Frame Sudoku by Richard (on 13. March 2018, 00:00) | 113 |  92 % |
| Wrinkled potato by Quiriqui (on 28. April 2023, 12:48) | 62 | 93 % |
| Identitätskrise (Variables Tapasyu 2) by usp (on 8. March 2014, 16:20) | 59 | 96 % |
| Little Killer Sandwiches Sudoku by Jesper (on 6. June 2020, 13:53) | 63 | 95 % |
| Killer Around the Corner by SudokuExplorer (on 20. April 2021, 01:00) | 67 | 95 % |
| Reign of Arrows 3 (Anti-knight, Arrows, Anti-XV) by juddimal (on 3. May 2025, 03:11) | 74 | 91 % |
| VvVwVvV by NicoD (on 15. July 2025, 05:30) | 81 | 94 % |
| Rivers and Islands Sudoku by matt383 (on 3. May 2020, 02:47) | 85 | 97 % |
| Roller Coaster mit Extras by Uhu (on 26. December 2017, 14:22) | 70 | 97 % |
| Bomb Sudoku #2 by Rotstein (on 7. July 2020, 05:00) | 16 | 95 % |
| XV Kropki Sudoku by Phistomefel (on 26. September 2020, 15:33) | 133 | 91 % |
| Parity Party XIII, "Power Hour" by glum_hippo (on 30. October 2020, 14:09) | 23 | 94 % |
| Pencil puzzle sudoku hybrid series #2 - Hashiwokakero sudoku by Aspartagcus (on 6. November 2020, 11:25) | 53 | 97 % |
| Irregular Compoundoku by athin (on 15. January 2021, 07:00) | 14 | 95 % |
| Sandwiched in Between by udukos (on 16. January 2021, 05:37) | 29 | 99 % |
| Squiggle by Lisztes (on 11. April 2021, 01:00) | 32 | 96 % |
| Six-pack Linked Sudokus #3 by Genomico (on 25. February 2021, 03:49) | 47 | 92 % |
| Killer Sudoku by abed hawila (on 30. March 2021, 12:58) | 46 | 94 % |
| 7 (Arrow X Sudoku) by ICHTUES (on 25. April 2021, 06:00) | 40 | 93 % |
| Decidoku by Innocuous (on 18. August 2021, 01:31) | 19 | 95 % |
