(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 | |
|---|---|---|---|
 | Battenburg Killer by MavericksJD (on 12. June 2021, 14:06) | 28 |  93 % |
| Sompeo (Encaged Whispers) by ICHTUES (on 31. July 2022, 06:00) | 66 | 94 % |
| Blast Off (Region Sum Killer Diagonal) by tallcat (on 9. June 2023, 20:18) | 99 | 97 % |
| Viper in the fog by Jolly Rogers (on 15. June 2024, 10:00) | 126 | 94 % |
| Balance by Scojo (on 3. October 2024, 21:31) | 59 | 95 % |
| Top Hat Boy by lmdemasi (on 4. September 2025, 13:12) | 28 | 95 % |
| The Rumbling by Justalilguy (on 26. September 2025, 14:06) | 30 | 91 % |
| Sudoku Variants Series (315) - Summing Up Sudoku by Richard (on 7. April 2021, 00:00) | 75 | 95 % |
| Wichtel 2018 (5): Japanische U-Bahn by wichtel (on 29. November 2019, 02:18) | 42 | 99 % |
| Under the Hill by Jay Dyer (on 16. January 2023, 22:51) | 51 | 96 % |
| 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 % |
| Eviction Notice (Slingshot/Numbered Rooms) by damo_89 (on 22. August 2025, 10:59) | 46 | 97 % |
| Roller Coaster mit Extras 4 by Uhu (on 22. February 2018, 09:27) | 65 | 100 % |
| Cacophony by zetamath (on 5. August 2021, 18:19) | 93 | 95 % |
| X---V*6 by NurglesGift (on 19. May 2025, 18:38) | 96 | 96 % |
| Differenz X Kakuro IV (kryptisch) by tuace (on 31. August 2014, 21:30) | 41 | 97 % |
| Spring Sudoku（1） by cdwg2000 (on 9. September 2020, 15:51) | 45 | 95 % |
| Fifth Amendment (Killer Diagonal Sudoku) by Agent (on 4. March 2022, 09:00) | 44 | 96 % |
| Archer Towers by Angelo (on 12. May 2022, 20:09) | 19 | 94 % |
