(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 | |
|---|---|---|---|
 | Japanese Sum Cave Cipher #12: Pentominous by KNT (on 26. January 2023, 04:41) | 40 |  99 % |
| Boxes of Paint (Colourful Killers) by The Book Wyrm (on 23. November 2023, 23:18) | 12 | 91 % |
| Space Mountain by IcyFruit (on 1. December 2023, 22:12) | 28 | 97 % |
| Japanese Japanese Sums Sums #2 by The Book Wyrm (on 12. March 2024, 21:51) | 20 | 99 % |
| Chaos Construction: Liars (8x8) by Gliperal (on 22. April 2024, 20:38) | 22 | 93 % |
| Bank Vault by mormagli (on 5. June 2024, 19:45) | 19 | 95 % |
| Factorial Cages by Nurator (on 13. August 2024, 10:48) | 12 | 90 % |
| Klein's Foggy Glasses by DubiousMobius (on 3. October 2024, 21:43) | 19 | 95 % |
| Doubler Trickery by Mad-Tyas (on 12. October 2024, 12:33) | 19 | 92 % |
| Sunshine by SudokuExplorer (on 26. January 2021, 02:00) | 41 | 98 % |
| Genome by Tyrgannus (on 7. July 2021, 21:33) | 41 | 97 % |
| Rivers and Islands Sudoku #2 (hard) by matt383 (on 27. May 2020, 14:12) | 39 | 96 % |
| Exploded Compass Sudoku by stephane.bura (on 7. January 2021, 20:00) | 34 | 100 % |
| Bharatanatyam (2T1L CC) by Xenonetix (on 13. August 2022, 00:22) | 35 | 97 % |
| Duplication by Xenonetix (on 28. July 2023, 00:00) | 35 | 97 % |
| German Whisper Cages by kolot (on 17. March 2022, 19:50) | 61 | 98 % |
| X-Sums / Skyscraper Killer Sudoku by KNT (on 16. September 2022, 18:17) | 54 | 98 % |
| Regional Scores by Big Tiger (on 16. December 2023, 13:45) | 30 | 98 % |
| Renban-na-na-na-na-na by SirSchmoopy (on 18. March 2022, 02:30) | 23 | 100 % |
| Grid Dancing by Bremster (on 4. June 2022, 05:52) | 52 | 98 % |
