(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 | |
|---|---|---|---|
 | A 38 III (toroidal) by tuace (on 28. October 2017, 13:19) | 22 |  99 % |
| Balance Loop Sudoku by Gliperal (on 15. December 2021, 21:07) | 49 | 95 % |
| Schrödinger's Deconstruction by mathpesto (on 19. June 2022, 13:57) | 45 | 98 % |
| Palindrome Arrow Sudoku by EliasKar (on 11. September 2021, 03:08) | 22 | 93 % |
| Rainy Night by FryTheGuy (on 6. December 2021, 17:17) | 26 | 99 % |
| Chaos Construction: Stitches by XeonRisq (on 18. February 2022, 01:00) | 21 | 97 % |
| Pentomino Sudoku by KNT (on 11. June 2022, 17:22) | 41 | 99 % |
| Skyscraper Sums Deconstruction by Tacosian (on 24. January 2024, 04:07) | 21 | 100 % |
| Runway (Killer sudoku with maximum totals + arrows) by Qodec (on 6. October 2024, 19:06) | 71 | 95 % |
| Chaos Skyscrapers by JoWovrin (on 17. December 2021, 03:37) | 21 | 97 % |
| Archer's Entropy 3: Peace by Mad-Tyas (on 14. September 2022, 17:22) | 21 | 92 % |
| Chaos Deconstruction: Japanese Sum by Phistomefel (on 13. February 2023, 20:00) | 103 | 98 % |
| Japanese Sums #1: Killer Cages by lerroyy (on 15. February 2023, 19:52) | 20 | 96 % |
| Killer Sudoku :) by LittleNightmaresLady (on 18. October 2024, 21:40) | 18 | 94 % |
| The Wheel by Mad-Tyas (on 10. December 2024, 17:40) | 18 | 93 % |
| Chaos Construction : Wrogn by lerroyy (on 8. June 2022, 20:59) | 64 | 98 % |
| Riverbank - Episode 4: Nessie by henrypijames (on 20. May 2022, 09:26) | 18 | 98 % |
| Working Nine To Five by fjam (on 8. January 2024, 20:03) | 19 | 95 % |
| Double-Crosser Deconstruction by Christounet (on 12. July 2024, 00:00) | 18 | 100 % |
| Dynamic Construction by Niverio (on 6. April 2022, 00:26) | 37 | 99 % |
