(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 | |
|---|---|---|---|
 | Knapp daneben Twin Killer II by Richard (on 1. January 2010, 12:00) | 36 |  94 % |
| LM 2017 Reste: Achterbahn (ohne Sicherheitsgurte) by pwahs (on 14. April 2017, 10:00) | 35 | 99 % |
| There is still life in my sandwich... by Sktx (on 15. May 2021, 00:49) | 17 | 95 % |
| Syzygy Stardust by David BOWie by mith (on 11. April 2022, 21:48) | 39 | 97 % |
| Watchtower sudoku by Lizzy01 (on 1. August 2022, 10:24) | 19 | 95 % |
| Double the Heat by Jay Dyer (on 17. September 2022, 21:55) | 38 | 99 % |
| Second Region X-Sums Chaos #2 by Elliptical (on 18. January 2023, 22:58) | 17 | 93 % |
| Disconnected Counting Chaos by wooferzfg (on 9. June 2024, 05:16) | 37 | 97 % |
| Erratic U-Bahn by Agent (on 13. June 2025, 09:00) | 18 | 100 % |
| Summation U-Bahn #3: Castle Wall by Agent (on 17. October 2023, 09:00) | 42 | 100 % |
| Arrow Sudoku - The Nightmare by emmettcito (on 19. January 2021, 20:36) | 32 | 98 % |
| The last call by filuta (on 18. April 2022, 17:38) | 27 | 94 % |
| Enantiodromia (Yin-Yang Chaos Construction, 8x8) by thoughtbyte (on 3. August 2022, 00:05) | 26 | 99 % |
| Crypto Rotating Japanese Pentopia with Skyscrapers for ibag by KNT (on 10. July 2023, 00:51) | 26 | 99 % |
| Janus (Chiaroscuro + U-Bahn) by sfushidahardy (on 15. May 2025, 01:25) | 27 | 100 % |
| Chaotic Wrogn [Tribute to DiMono] by Undar_Beyond (on 28. December 2020, 08:14) | 95 | 97 % |
| Chaos Construction: Border Sums by KNT (on 24. April 2022, 22:24) | 59 | 95 % |
| Goliath by Jay Dyer (on 25. July 2023, 16:03) | 38 | 97 % |
| Cave / Directionless Yajilin Permaculture by Agent (on 21. August 2024, 09:00) | 36 | 100 % |
| Entropic Loop Chaos by yttrio (on 9. February 2024, 19:28) | 81 | 96 % |
