(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 | |
|---|---|---|---|
 | Foggy Loop (FOW) by antiknight (on 28. August 2023, 04:47) | 124 |  92 % |
| Think Outside the Box by Jrosas (on 8. April 2024, 07:45) | 53 | 91 % |
| Killer X Sudoku #2 by Phistomefel (on 3. February 2020, 16:17) | 97 | 90 % |
| Slalom mit Torstangen, Teil 4 by pirx (on 2. October 2012, 21:44) | 33 | 97 % |
| Collatz's Modifiers by mathpesto (on 12. September 2022, 03:53) | 30 | 96 % |
| Alfonso and Lori by zetamath (on 26. March 2023, 15:51) | 73 | 95 % |
| Fogrotto by mathpesto (on 17. December 2022, 15:29) | 185 | 96 % |
| 真笑Puzzles034--69Sandwiches (7)--XY Index2 by cdwg2000 (on 14. March 2021, 09:51) | 16 | 100 % |
| Mama Python 2 (Thermo Snake Sudoku) by peterchayward (on 10. April 2021, 04:31) | 21 | 98 % |
| Theorist's Key Change by Tyrgannus (on 14. November 2021, 21:04) | 18 | 91 % |
| X-sums Parity Confetti by Playmaker6174 (on 24. January 2022, 08:32) | 31 | 99 % |
| Louisville by ICHTUES (on 6. February 2022, 06:00) | 32 | 96 % |
| Chaos Construction: Equality by SSG (on 27. February 2022, 07:08) | 16 | 97 % |
| Rectangle Rodeo (Region Sum Lines) by Mad-Tyas (on 2. March 2022, 22:42) | 21 | 90 % |
| Building The Unknown 2 by Joseph nehme (on 29. April 2022, 16:49) | 15 | 93 % |
| WheelbArrows by Mountainfarmer (on 18. August 2022, 10:47) | 20 | 98 % |
| Clone College by SSG (on 17. January 2023, 07:17) | 37 | 95 % |
| Chaos Construction: Oblivion by XeonRisq (on 26. January 2023, 06:00) | 17 | 97 % |
| Half-Life² by ViKingPrime (on 10. February 2023, 15:32) | 14 | 95 % |
| Whispering Snakeban by yanggang (on 26. April 2024, 19:31) | 14 | 98 % |
