(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 | |
|---|---|---|---|
 | Unique Killers by Yawnus (on 24. February 2023, 11:50) | 52 |  96 % |
| Leaning Tower by marty_sears (on 4. November 2023, 09:10) | 105 | 99 % |
| Tapa-Höhle 1 by usp (on 13. March 2015, 00:00) | 56 | 91 % |
| Cat Fun by Scojo (on 24. November 2024, 07:55) | 62 | 95 % |
| Smog in the City (Fog, Skyscrapers) by Chilly (on 13. January 2025, 19:52) | 63 | 92 % |
| Wichtel 2017 (9): 26341413052226052223243316041107251607 by wichtel (on 3. October 2018, 05:06) | 26 | 96 % |
| Snake Egg Sum Sudoku by Quarterthru (on 20. July 2020, 20:00) | 16 | 94 % |
| Slingshot Sudoku - Return of the Invisible Killers by stephane.bura (on 13. August 2020, 20:00) | 14 | 95 % |
| Little Killer X Sudoku by Willy Wonka (on 10. August 2020, 11:02) | 68 | 97 % |
| Octothorpe by Konzert (on 27. February 2021, 20:23) | 20 | 91 % |
| Cracked by abed hawila (on 20. April 2021, 01:54) | 12 | 100 % |
| Do Have A Go! by virtual (on 19. May 2021, 06:45) | 12 | 91 % |
| Kaged Knights by kuraban (on 27. June 2021, 02:50) | 32 | 98 % |
| Arrows of Central Tendency by mathpesto (on 14. November 2021, 21:48) | 15 | 91 % |
| Oreo by the_cogito (on 16. January 2022, 18:07) | 12 | 95 % |
| Unique Arrow Sudoku by tsergiiv (on 19. March 2022, 08:07) | 15 | 93 % |
| BTNCA by ICHTUES (on 3. July 2022, 06:00) | 44 | 96 % |
| Chain Link Fence [Arrow Sudoku] by Malrog (on 25. August 2022, 13:36) | 27 | 93 % |
| Steamed Hams by Perladel (on 12. October 2022, 13:03) | 63 | 96 % |
| Wonky Numbers by ThePedallingPianist (on 28. November 2022, 23:09) | 14 | 94 % |
