(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 Sudoku - The Nightmare by emmettcito (on 19. January 2021, 20:36) | 32 |  98 % |
| Ninelives [X-Sums Chaos Construction] by Panthera (on 22. June 2021, 19:30) | 25 | 100 % |
| Gridlock by FryTheGuy (on 14. November 2021, 01:13) | 26 | 98 % |
| Chaos Skyscrapers by JoWovrin (on 17. December 2021, 03:37) | 26 | 98 % |
| The last call by filuta (on 18. April 2022, 17:38) | 27 | 94 % |
| Enantiodromia (Yin-Yang Chaos Construction, 8x8) by thoughtbyte (on 3. August 2022, 00:05) | 27 | 99 % |
| Sudoku O.W.L. by Nahileon (on 10. October 2022, 21:25) | 24 | 100 % |
| Crypto Rotating Japanese Pentopia with Skyscrapers for ibag by KNT (on 10. July 2023, 00:51) | 28 | 99 % |
| Entropic Loop Chaos by yttrio (on 9. February 2024, 19:28) | 83 | 96 % |
| [PAC] Triple Japanese Sums by The Book Wyrm (on 24. October 2025, 19:01) | 31 | 99 % |
| Copycat Fun by Scojo (on 8. December 2025, 04:35) | 30 | 97 % |
| Chaos Construction: Border Sums by KNT (on 24. April 2022, 22:24) | 60 | 95 % |
| Chaos Construction: Red Team / Blue Team by KNT (on 4. May 2024, 06:24) | 60 | 95 % |
| Steel Vengeance (Rollercoaster Chaos Deconstruction) by tallcat (on 2. September 2024, 08:00) | 60 | 98 % |
| Taco Bowl 3 - Ring Of Fire by DiMono (on 19. March 2021, 16:15) | 44 | 99 % |
| Colossal Nurikabe Sudoku by Christounet (on 13. June 2023, 00:47) | 43 | 100 % |
| Fill Rank Fullomino by Myxo (on 31. May 2023, 13:26) | 57 | 98 % |
| Colossal Fillomino with Sandwich Sudoku by MagnusJosefsson (on 28. September 2022, 15:50) | 73 | 100 % |
| -45 Killer by Mesmer (on 21. August 2020, 14:39) | 16 | 98 % |
| Fireworks (Killer Arrow Sudoku) by FryTheGuy (on 2. June 2021, 07:12) | 20 | 91 % |
