(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 | |
|---|---|---|---|
 | Pandora's Renban by JeffWajes (on 18. January 2023, 21:12) | 48 |  97 % |
| Zoom Out by Myxo (on 30. July 2024, 12:22) | 111 | 99 % |
| Killer Windrad by tuace (on 30. July 2016, 14:45) | 44 | 98 % |
| Irrwisch Sudoku: Sandwich by Gliperal (on 22. May 2023, 11:30) | 49 | 99 % |
| Snakes of Chaos by Andrewsarchus (on 14. January 2025, 15:59) | 109 | 99 % |
| Sudoku Variants Series (373) - Four Winds Killer by Richard (on 1. June 2022, 01:00) | 59 | 93 % |
| Full Rank Sandwich by RockyRoer (on 5. June 2022, 03:22) | 54 | 100 % |
| Repeater by mathpesto (on 19. March 2022, 04:47) | 52 | 99 % |
| Flaschenpost (Nurikabe Cipher Sudoku) by Agent (on 4. October 2022, 09:00) | 57 | 98 % |
| Red Lodge, Montana (Sudoku-Creek Hybrid) by mathpesto (on 24. December 2023, 17:10) | 118 | 97 % |
| Killer - Region Sum Lines - Cave by abed hawila (on 9. May 2022, 20:41) | 68 | 100 % |
| Ma'at's Judgement - The Weighing of the Heart (Chaos Construction) by Chilly (on 22. November 2022, 16:58) | 80 | 100 % |
| X-Ray Vision (Yin Yang X-Sums Sudoku) by Agent (on 6. September 2022, 09:00) | 72 | 98 % |
| Chaotic Equality by Knickolas (on 8. December 2022, 21:07) | 83 | 98 % |
| 5-ABCtje by Richard (on 28. August 2009, 09:01) | 65 | 90 % |
| Der verlorene Schlüssel by berni (on 5. March 2010, 14:34) | 51 | 98 % |
| Alpträume by ibag (on 27. March 2017, 23:55) | 39 | 99 % |
| Machtwechsel in Rätselhausen by Statistica (on 1. December 2018, 18:18) | 30 | 99 % |
| 4 Corners Killer Sudoku by Strosahl (on 30. September 2020, 17:20) | 35 | 94 % |
| Confetti Sums Killer Sudoku by Jesper (on 24. February 2021, 15:10) | 47 | 99 % |
