(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 | |
|---|---|---|---|
 | Viper in the fog by Jolly Rogers (on 15. June 2024, 10:00) | 127 |  95 % |
| Little Killer Sudoku by Philipp Huber (on 5. July 2020, 13:02) | 36 | 91 % |
| Diagonal Skyscraper Sudoku by MagnusJosefsson (on 15. April 2021, 16:32) | 41 | 96 % |
| Killed Bulbs and Killer Cages - Thermo(?) Killer Sudoku by Cane_Puzzles (on 18. April 2021, 13:30) | 41 | 96 % |
| Good Luck, Bad Luck by oberon (on 21. February 2022, 20:29) | 46 | 97 % |
| Domino Fever (Entropy Edition) by Mad-Tyas (on 21. February 2022, 23:32) | 75 | 94 % |
| Memento Regem by LeaVulpina (on 10. March 2024, 00:23) | 35 | 93 % |
| Squishdoku by Jay Dyer (on 21. November 2023, 00:36) | 105 | 95 % |
| Sudoku Variants Series (288) - Battlefield Sudoku by Richard (on 30. September 2020, 00:00) | 70 | 97 % |
| Wichtel 2019 (10): Die Wohnquartiere der Wichtel by wichtel (on 2. November 2020, 19:20) | 52 | 100 % |
| Dude where's my XV? by PetLov (on 6. February 2021, 21:06) | 33 | 92 % |
| Battenburg Killer by MavericksJD (on 12. June 2021, 14:06) | 28 | 93 % |
| Blast Off (Region Sum Killer Diagonal) by tallcat (on 9. June 2023, 20:18) | 99 | 97 % |
| double negative by arctan (on 24. September 2024, 22:02) | 29 | 95 % |
| Balance by Scojo (on 3. October 2024, 21:31) | 59 | 95 % |
| Top Hat Boy by lmdemasi (on 4. September 2025, 13:12) | 29 | 95 % |
| Sudoku Variants Series (315) - Summing Up Sudoku by Richard (on 7. April 2021, 00:00) | 77 | 95 % |
| Wichtel 2018 (5): Japanische U-Bahn by wichtel (on 29. November 2019, 02:18) | 42 | 99 % |
| Neapolitan by pieguy (on 19. June 2023, 18:16) | 55 | 95 % |
| sphinx of black quartz by aqjhs (on 4. October 2024, 01:40) | 113 | 94 % |
