(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 | |
|---|---|---|---|
 | Thermo-Sudoku: Some Assembly Required by trivial171 (on 6. May 2020, 04:10) | 31 |  99 % |
| Unique Aquarium Sudoku by Sam Knott (on 22. September 2020, 15:17) | 54 | 99 % |
| BetSandwichween by LKegel (on 10. February 2021, 12:32) | 30 | 92 % |
| Antiknight Whispers by thoughtbyte (on 12. February 2022, 08:58) | 29 | 91 % |
| Bounds of Luck (Whisper MinMax) by tallcat (on 21. September 2022, 03:46) | 55 | 95 % |
| Cactus [German Whispers] by Malrog (on 8. January 2023, 01:56) | 33 | 93 % |
| S-Thermo by Prof.Dori (on 11. May 2023, 12:42) | 31 | 93 % |
| TetromUNO by yanggang (on 30. May 2024, 20:09) | 29 | 95 % |
| Demiparure by mormagli (on 15. June 2024, 17:28) | 25 | 94 % |
| Sum Fillomino by AnalyticalNinja (on 10. September 2024, 18:10) | 82 | 98 % |
| 14 Givens by lepton (on 4. February 2024, 04:34) | 96 | 95 % |
| Prime Killer Sudoku by udukos (on 25. July 2020, 17:54) | 46 | 95 % |
| Times Square by grkles (on 5. November 2021, 16:56) | 37 | 94 % |
| Glatt by ICHTUES (on 23. October 2022, 06:00) | 48 | 94 % |
| Cornerstones by Jagga (on 26. November 2022, 09:06) | 40 | 98 % |
| Modesty (Equalines Sudoku) by Mad-Tyas (on 21. February 2023, 09:16) | 50 | 98 % |
| *100* Doppelter Pentomino-Rundweg by Richard (on 17. June 2009, 21:00) | 97 | 95 % |
| Thermo Dot by FullDeck-Missing (on 4. April 2023, 23:54) | 85 | 92 % |
| Killeriana: Ungleichungskiller by Pyrrhon (on 8. October 2009, 14:35) | 89 | 96 % |
| Die Kryptos - S03E04: Summon by tuace (on 30. October 2018, 10:14) | 49 | 99 % |
