(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 | |
|---|---|---|---|
 | Arrow Forest by PotatoHead21 (on 28. September 2021, 09:51) | 15 |  91 % |
| Even Small Prime by FryTheGuy (on 13. December 2021, 16:28) | 27 | 99 % |
| Paper Snowflake (Irregular, Killer) by Chefofdeath (on 28. May 2023, 04:46) | 14 | 95 % |
| Manifold Paths (Advanced Black Hole) by heliopolix (on 16. June 2023, 02:14) | 13 | 100 % |
| Quicksort by filuta (on 29. June 2023, 14:15) | 11 | 100 % |
| Entropy Equilibrium by Mad-Tyas (on 14. November 2023, 09:51) | 14 | 91 % |
| Does Phistomefel's Ring Still Apply? by bodemeister (on 23. February 2024, 08:43) | 13 | 98 % |
| Japanese Sums Cave Cipher - KNT by ONeill (on 27. August 2024, 12:49) | 28 | 99 % |
| Wichtels Rätselsommer 2024 (5): Wätsel-Weihnacht by wichtel (on 29. August 2024, 20:23) | 12 | 95 % |
| Toil and Trouble by Scojo (on 30. May 2025, 22:45) | 24 | 94 % |
| Blue Prince by vfig (on 21. June 2025, 06:34) | 14 | 91 % |
| Camera Obscura (Odd-Even Coded Teleportation Cycle Sums Sudoku) by Feadoor (on 4. August 2025, 09:29) | 13 | 91 % |
| Thinkies (Miracle Chaos Construction) by purpl (on 12. June 2022, 18:12) | 36 | 98 % |
| Whirlpool by FryTheGuy (on 26. August 2021, 17:16) | 26 | 96 % |
| Digital Loop by mathpesto (on 22. May 2025, 22:44) | 44 | 96 % |
| Pentomino Sudoku by KNT (on 11. June 2022, 17:22) | 45 | 97 % |
| Japanese Dominos by KNT (on 14. March 2024, 15:59) | 48 | 99 % |
| Ten-Oh (10-Lines sudoku) by Qodec (on 21. May 2023, 18:31) | 74 | 97 % |
| Chaos Skyscrapers by JoWovrin (on 17. December 2021, 03:37) | 24 | 98 % |
| Chaos in the Knighttime by SenatorGronk (on 5. October 2022, 15:56) | 23 | 99 % |
