(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 | |
|---|---|---|---|
 | Dyscalculia by Lorena (on 7. February 2025, 15:30) | 31 |  93 % |
| One Too Many (Japanese Sums, Tiny Cave) by .proxz14 (on 2. March 2025, 14:43) | 20 | 94 % |
| Difference Of Squares by MathGuy_12 (on 6. March 2025, 16:28) | 27 | 98 % |
| Minus-or-Plus by FischmitFahrrad (on 16. March 2025, 22:02) | 17 | 95 % |
| Akari Sums by Oripy (on 7. April 2025, 12:00) | 18 | 93 % |
| Déjà Vu by ndsurgenor (on 6. April 2025, 11:00) | 18 | 93 % |
| Dutch Flat Mates: Y-Sums by Crusader175 (on 18. June 2025, 08:36) | 54 | 94 % |
| Colorful symmetry by Adrian71 (on 29. August 2025, 18:01) | 16 | 94 % |
| Wichtels Rätselherbst 2025 (1): Wichtelkabbelei by wichtel (on 1. October 2025, 20:25) | 14 | 100 % |
| Suguru Chaos Deconstruction by mathpesto (on 12. February 2022, 23:45) | 197 | 99 % |
| Discombobulation by NicoD (on 9. May 2025, 05:30) | 120 | 97 % |
| seven swans a-swimmin' by aqjhs (on 18. December 2024, 03:45) | 116 | 97 % |
| Golden Palindromes by MathGuy_12 (on 23. September 2025, 03:28) | 122 | 97 % |
| Black-dot Mamba by yttrio (on 10. November 2023, 20:55) | 104 | 98 % |
| LM 2016 - Leftover: Yajilin by lupo (on 15. July 2016, 20:16) | 70 | 93 % |
| Sudoku Variants Series (415) - Parity Poopers by Richard (on 14. March 2025, 12:00) | 70 | 96 % |
| Hungarian Tapa / Roller Coaster (1) by KNT (on 23. September 2022, 20:45) | 65 | 100 % |
| Battlefield Sudoku by Realshaggy (on 31. May 2020, 13:08) | 61 | 96 % |
| Sudoku Variants Series (328) - Sudoku Heatmap by Richard (on 7. July 2021, 00:00) | 61 | 94 % |
| Battle With The Archers 16: Judgment Trio by Playmaker6174 (on 17. September 2021, 12:12) | 56 | 97 % |
