(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 | |
|---|---|---|---|
 | Tentrik Meditation (with mellowrobinson) by sujoyku (on 3. August 2025, 08:29) | 44 |  97 % |
| GW-Bahn (German Whisper U-Bahn) by cyddrdrd (on 27. September 2025, 00:00) | 20 | 100 % |
| Fillomino-ish Killer Sudoku by SirWoezel (on 25. November 2020, 16:21) | 55 | 99 % |
| Three of Diamonds by zetamath (on 20. February 2023, 16:07) | 55 | 93 % |
| Seesaw (Killer Only Sudoku) by Celery (on 10. December 2023, 22:34) | 55 | 98 % |
| Too Close For Comfort by Niverio (on 3. March 2024, 16:11) | 53 | 96 % |
| Japanische Summen-Koralle 2358 by Uhu (on 27. December 2016, 14:23) | 55 | 98 % |
| Schrödinger's Arrows by starwarigami (on 14. January 2022, 04:34) | 30 | 96 % |
| Kill Kill (Doubler Killer) by ICHTUES (on 28. August 2022, 06:00) | 61 | 98 % |
| 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) | 30 | 98 % |
| Unique Value Deconstruction by sfushidahardy (on 27. June 2024, 18:13) | 33 | 96 % |
| Twin Killer Sudoku III by Richard (on 8. July 2009, 14:19) | 89 | 93 % |
| In Between the Spaces by XeonRisq (on 12. October 2022, 04:00) | 41 | 93 % |
| Chaotic Pointers by arbitrary (on 7. December 2024, 23:49) | 38 | 93 % |
| Chromosomes by ThePedallingPianist (on 3. January 2023, 01:15) | 116 | 96 % |
| 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) | 73 | 93 % |
| Divisibility Squares Sudoku by ProwlingTiger (on 16. July 2020, 03:33) | 21 | 97 % |
