(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 | |
|---|---|---|---|
 | Killer Sudoku(003) by cdwg2000 (on 4. September 2020, 01:04) | 52 |  98 % |
| Gabe Ruth hits a homerun by SirWoezel (on 28. April 2021, 18:49) | 28 | 96 % |
| Cycle (Between lines sudoku) by Lizzy01 (on 8. September 2021, 10:45) | 21 | 97 % |
| Wordless Kakuro by qiuyanzhe (on 26. November 2021, 08:34) | 21 | 92 % |
| 10-in-9 Killer Sudoku by KNT (on 10. May 2022, 01:14) | 44 | 97 % |
| Schrodinger's Split Peas by SamuPiano (on 12. July 2024, 15:44) | 42 | 97 % |
| Japanese Slitherlink by KNT (on 27. October 2024, 22:43) | 45 | 100 % |
| Double negative by filuta (on 26. January 2025, 12:28) | 21 | 100 % |
| Colorimetry (Four Color Pentomino Sums) by Agent (on 19. August 2025, 09:00) | 40 | 99 % |
| BYO Kropki Cages by mathpesto (on 10. December 2022, 02:33) | 74 | 99 % |
| Chaos Construction: Killer Cages by KNT (on 4. April 2022, 23:31) | 125 | 96 % |
| Chequered Arromino #2 by Phistomefel (on 25. May 2023, 20:32) | 106 | 99 % |
| Les Flèches by Joseph nehme (on 15. May 2021, 07:16) | 28 | 90 % |
| Thonk? by purpl (on 3. May 2022, 00:26) | 27 | 95 % |
| Meidjuluk II (N=25) by glum_hippo (on 1. June 2023, 00:00) | 52 | 99 % |
| Dynamic Domino Sums by Jolly Rogers (on 22. May 2025, 18:53) | 35 | 93 % |
| Japanese Nurikabe (1) by KNT (on 4. September 2022, 05:44) | 61 | 97 % |
| Advanced Kinematics (Projected Sum Arrow) by tallcat (on 6. April 2022, 20:08) | 35 | 91 % |
| Thermal Equilibrium (Chaos Construction) by Agent (on 19. July 2022, 09:00) | 100 | 100 % |
| Balanced Chaos by fritzdis (on 29. November 2022, 16:24) | 119 | 97 % |
