(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 | |
|---|---|---|---|
 | Roman Hieroglyph by lepton (on 17. January 2023, 17:20) | 20 |  97 % |
| Poison Pill Killer by JeffWajes (on 4. September 2023, 20:30) | 40 | 96 % |
| U-Bahn with Extra Regions by wooferzfg (on 2. July 2024, 07:46) | 18 | 100 % |
| Chaos Construction: Exclusions by KNT (on 1. May 2024, 18:08) | 122 | 93 % |
| Jörmungandr by Jay Dyer (on 2. June 2022, 13:46) | 127 | 99 % |
| Sudokutown is That Way by Aaronomys (on 20. February 2022, 14:26) | 29 | 99 % |
| Tonfa by Blashyrkh (on 14. April 2023, 09:41) | 31 | 94 % |
| Sackgassen by Myxo (on 15. August 2023, 05:27) | 30 | 96 % |
| Onion by the_cogito (on 7. November 2023, 17:10) | 69 | 99 % |
| Neodymium (Double Cave Japanese Sums) by Agent (on 4. June 2024, 09:00) | 34 | 99 % |
| Now the People Will Know We Were Here by ViKingPrime (on 17. April 2024, 16:15) | 45 | 97 % |
| Skycagers (Build Your Own Killer Sudoku) by Agent (on 17. January 2023, 09:00) | 72 | 99 % |
| Chaos FilloSudokumino: Deconstruction by MagnusJosefsson (on 19. January 2023, 16:12) | 67 | 97 % |
| Killer Sudoku(002) by cdwg2000 (on 26. August 2020, 08:14) | 25 | 96 % |
| Little Killer Arrow Sudoku by Phistomefel (on 2. March 2021, 11:50) | 64 | 98 % |
| Sudokoban by DiMono (on 19. January 2023, 16:35) | 62 | 96 % |
| A Narrow Region by PotatoHead21 (on 21. February 2023, 20:25) | 11 | 95 % |
| Reflection by Chad (on 25. July 2023, 18:29) | 24 | 98 % |
| The Ankheg (Zippular Lines #4) by heliopolix (on 30. December 2023, 16:36) | 13 | 98 % |
| Chaos Destruction X-Sums by lepton (on 18. February 2024, 08:07) | 29 | 94 % |
