(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 | |
|---|---|---|---|
 | 195? 519? 951? by twototenth (on 20. September 2022, 08:00) | 58 |  97 % |
| I'm going deeper underground... [Snake U-Bahn] by Christounet (on 1. December 2023, 14:13) | 29 | 98 % |
| Chromosomes by ThePedallingPianist (on 3. January 2023, 01:15) | 110 | 96 % |
| Twin Killer Sudoku III by Richard (on 8. July 2009, 14:19) | 88 | 93 % |
| 1. Teil der Trilogie: Ein verliebter Rundweg by berni (on 28. September 2010, 12:34) | 75 | 100 % |
| In Between the Spaces by XeonRisq (on 12. October 2022, 04:00) | 41 | 93 % |
| Skyscraper Slingshot Sudoku by Piatato (on 2. February 2023, 21:43) | 38 | 100 % |
| Chaotic Pointers by arbitrary (on 7. December 2024, 23:49) | 38 | 93 % |
| Archers Defending the Castle by GBPack (on 9. May 2021, 06:41) | 52 | 98 % |
| Zwei Bärenfreunde by berni (on 11. August 2010, 14:16) | 21 | 92 % |
| Die Kryptos - S04E05: U-Bahn unter Hochhäusern by tuace (on 21. January 2020, 08:06) | 49 | 100 % |
| Avada Kedavra - A Magic Square Killer by Philipp Huber (on 8. July 2020, 22:38) | 72 | 93 % |
| Divisibility Squares Sudoku by ProwlingTiger (on 16. July 2020, 03:33) | 21 | 97 % |
| Triple Decker by Mimaamakim (on 29. August 2021, 20:28) | 34 | 98 % |
| Hangover by Realshaggy (on 13. February 2022, 17:03) | 41 | 97 % |
| Valiant Viper in the King's Garden (Chess Snake Sudoku) by Nordy (on 5. April 2022, 01:20) | 31 | 95 % |
| Chaos Construction: diagonals by Prutsbeest (on 23. May 2022, 07:00) | 33 | 97 % |
| Entropy Focus by Mad-Tyas (on 8. September 2022, 14:54) | 46 | 96 % |
| Full Quads by mormagli (on 7. October 2022, 16:52) | 24 | 97 % |
| Equilibrium by Mad-Tyas (on 1. November 2022, 09:41) | 65 | 98 % |
