(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 | |
|---|---|---|---|
 | Ghost Python 2 (Clone Snake Sudoku) by peterchayward (on 29. July 2020, 19:16) | 45 |  95 % |
| Build Your Own Anti-Knight Sudoku by DiMono (on 24. October 2020, 17:41) | 20 | 94 % |
| Distant Relations #1 by Big Tiger (on 25. January 2021, 10:00) | 20 | 94 % |
| Whirlpool by Xailran (on 20. September 2021, 13:04) | 17 | 91 % |
| Dumbbells by djorr (on 29. March 2022, 14:00) | 22 | 97 % |
| Pieces of the Puzzle by grkles (on 22. February 2022, 01:39) | 20 | 99 % |
| Clapping on the 1 and 3 by cristophermoore (on 6. November 2023, 00:00) | 42 | 93 % |
| Circle Squared by Ridhwan (on 2. January 2024, 03:27) | 29 | 97 % |
| Prison Negativity by Prof.Dori (on 30. January 2024, 18:54) | 19 | 91 % |
| Medley by Playmaker6174 (on 2. September 2024, 08:00) | 67 | 94 % |
| Hammerhead Shark by Lizzy01 (on 18. February 2025, 16:28) | 48 | 91 % |
| Branches (arrow sudoku) by Aspartagcus (on 12. September 2023, 13:44) | 67 | 94 % |
| Warp Speed by The Bard (on 16. October 2024, 00:02) | 179 | 96 % |
| Switch by fuxia (on 12. March 2023, 01:13) | 55 | 93 % |
| Lockset by Xenonetix (on 25. June 2023, 21:12) | 52 | 91 % |
| Central Difference Method by JMoat13 (on 25. August 2023, 23:06) | 52 | 92 % |
| One Challenge Remaining (Flinty & Palpot) by palpot (on 11. July 2024, 13:36) | 27 | 91 % |
| XV Kropki Sudoku by Philipp Huber (on 28. November 2020, 15:14) | 76 | 94 % |
| Siamese Rundweg Sudoku Twins by pokerke (on 2. December 2010, 21:35) | 47 | 96 % |
| Sudoku Variants Series (179) - Outside Killer Sudoku by Richard (on 2. May 2017, 00:00) | 103 | 95 % |
