(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 | |
|---|---|---|---|
 | Wichtel 2017 (10): Luftige Flotte an Wolkenmousse in inversem Schneegestöber by wichtel (on 17. October 2018, 07:04) | 24 |  99 % |
| A Bridge Before the Rainbow by fritzdis (on 20. March 2021, 21:35) | 13 | 93 % |
| The Digits Are Paid Actors by Lizzy01 (on 5. November 2022, 21:40) | 26 | 99 % |
| A Narrow Region by PotatoHead21 (on 21. February 2023, 20:25) | 13 | 95 % |
| Unlucky Sevens by noswald (on 7. June 2023, 04:52) | 44 | 94 % |
| Eclipsed Whispers by Space_man (on 7. May 2024, 05:52) | 39 | 95 % |
| Neodymium (Double Cave Japanese Sums) by Agent (on 4. June 2024, 09:00) | 43 | 99 % |
| Chaos Incorporated by Kafkapharnaum (on 4. April 2025, 01:23) | 28 | 100 % |
| Skycagers (Build Your Own Killer Sudoku) by Agent (on 17. January 2023, 09:00) | 79 | 99 % |
| Convergence by TotallyNormalCat (on 18. February 2021, 22:30) | 31 | 98 % |
| Unboxing by mathpesto (on 11. May 2023, 05:11) | 68 | 97 % |
| Reef by zetamath (on 26. June 2023, 03:35) | 120 | 97 % |
| The Landmark of Entropia by Mad-Tyas (on 30. March 2024, 09:11) | 35 | 93 % |
| Sunset Cave by wooferzfg (on 4. May 2025, 08:37) | 37 | 96 % |
| Productivity Killer (BYOK+) by SeveNateNine (on 18. October 2023, 02:45) | 58 | 95 % |
| The Barrel (Arrow Sudoku) by tallcat (on 18. April 2021, 05:29) | 89 | 98 % |
| Zweiter Pfeilchenstrauß by glum_hippo (on 24. August 2020, 17:26) | 24 | 93 % |
| Parity Party XXII, "Party Hearty" by glum_hippo (on 4. January 2022, 04:19) | 42 | 99 % |
| Antimatter by zetamath (on 14. January 2022, 01:53) | 42 | 94 % |
| Chaos Sums by wooferzfg (on 28. December 2022, 15:49) | 41 | 98 % |
