(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 | |
|---|---|---|---|
 | Perspective by MSDOS (on 19. February 2026, 00:05) | 60 |  97 % |
| Tapa III by yureklis (on 24. March 2010, 22:44) | 92 | 95 % |
| Reflections (Antiknight Killer Sudoku) by Phistomefel (on 11. September 2022, 12:34) | 183 | 96 % |
| It's a Non-Factor by SSG (on 26. October 2023, 09:24) | 51 | 96 % |
| Think Outside the Box by Jrosas (on 8. April 2024, 07:45) | 54 | 91 % |
| Kaleidoscope by Scojo (on 8. April 2026, 06:49) | 52 | 93 % |
| Copycat Burgh-lars (Collab with ChinStrap, Calvinball, Sotehr, and MathGuy_12) by Scojo (on 13. April 2026, 18:19) | 48 | 99 % |
| Entropic Pieces by Myxo (on 11. March 2023, 19:35) | 34 | 98 % |
| Killomino (Sudoku Fillomino Killer) by purpl (on 21. December 2024, 17:51) | 32 | 96 % |
| Too Many Arrows by Md88keys (on 12. August 2025, 19:08) | 42 | 91 % |
| 9x9 Chaos Constructions: X-Sums and Arrows by abed hawila (on 19. June 2021, 19:51) | 50 | 98 % |
| Doppelt (Double Arrow) by tallcat (on 17. September 2021, 16:48) | 45 | 96 % |
| Slalom mit Torstangen, Teil 4 by pirx (on 2. October 2012, 21:44) | 34 | 97 % |
| Wichtelkalender 2012 (6) by wichtel (on 17. October 2012, 20:12) | 44 | 99 % |
| Position Sums mit Kropki-Paaren by glum_hippo (on 8. February 2021, 15:41) | 32 | 96 % |
| Mama Python 2 (Thermo Snake Sudoku) by peterchayward (on 10. April 2021, 04:31) | 22 | 98 % |
| Rectangle Rodeo (Region Sum Lines) by Mad-Tyas (on 2. March 2022, 22:42) | 24 | 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) | 21 | 98 % |
| Collatz's Modifiers by mathpesto (on 12. September 2022, 03:53) | 33 | 96 % |
