(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 | |
|---|---|---|---|
 | Juosan Parity Parade by kolot (on 9. November 2021, 13:31) | 19 |  99 % |
| Sum-thing's Wrogn by Jay Dyer (on 5. February 2022, 13:43) | 21 | 99 % |
| Fireworks and Firecrackers by Emphyrio (on 20. March 2022, 01:15) | 23 | 94 % |
| Nurikabe Sweeper Sudoku by KNT (on 23. May 2022, 01:37) | 61 | 98 % |
| Sudoku Variants Series (385) - Consecutive Sums Sudoku by Richard (on 21. September 2022, 02:00) | 91 | 98 % |
| Disturbed Balance by lepton (on 19. December 2022, 20:35) | 28 | 99 % |
| Difference by mormagli (on 4. March 2023, 05:59) | 20 | 97 % |
| Parity Loop #2: Irregular by Paletron (on 5. September 2023, 11:10) | 18 | 98 % |
| Ƨ Slithering Loop Ƨ by ElChiglia (on 14. October 2023, 08:05) | 46 | 92 % |
| Can You Count the Whispers? by Tobias Brixner (on 26. May 2024, 16:07) | 48 | 96 % |
| Trapped by mathpesto (on 25. August 2024, 05:18) | 38 | 91 % |
| gegenübertragung by aqjhs (on 8. November 2024, 09:13) | 20 | 90 % |
| Activated Cage Totals by RockyRoer (on 8. November 2024, 14:41) | 17 | 92 % |
| Tridoku with Modifers by Chad (on 28. December 2024, 20:56) | 16 | 90 % |
| Q-Bahn (U-Bahn Octoquadri) by the_cogito (on 9. May 2025, 20:12) | 28 | 100 % |
| Eternal Recurrence by Kafkapharnaum (on 11. October 2025, 23:11) | 24 | 95 % |
| AadBC's by MathGuy_12 (on 25. February 2026, 03:59) | 17 | 92 % |
| Gatekeeper by IcyFruit (on 27. March 2025, 13:26) | 121 | 96 % |
| Heated Entropy by Mad-Tyas (on 14. December 2021, 00:10) | 74 | 97 % |
| Whisper Doublers by yttrio (on 3. March 2023, 05:09) | 68 | 97 % |
