(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 | |
|---|---|---|---|
 | Outside Killer U-Bahn by the_cogito (on 8. July 2025, 17:16) | 35 |  99 % |
| Deconstruction: Region Sums by Jay Dyer (on 24. April 2022, 22:14) | 55 | 99 % |
| Purple Archery Arrows by antiknight (on 9. October 2022, 17:25) | 63 | 95 % |
| Summation U-Bahn Cipher by Agent (on 3. October 2023, 09:00) | 55 | 100 % |
| Century (Counting Circles + Numbered Rooms) by tallcat (on 29. May 2024, 08:00) | 58 | 98 % |
| Too hot to hoot! - A Thermo Palindrome Sudoku by Philipp Huber (on 18. August 2020, 19:39) | 27 | 98 % |
| Tilted Mirror - Palindrome Killer Sudoku by Tyrgannus (on 27. March 2021, 05:26) | 25 | 98 % |
| Wichtel 2020 (7): Ärger in der Wichtelwerkstatt by wichtel (on 15. September 2021, 20:20) | 22 | 100 % |
| Surround Set by PrimeWeasel (on 11. February 2022, 12:12) | 22 | 98 % |
| Repeat Prescription by Jay Dyer (on 21. July 2024, 00:11) | 53 | 97 % |
| I forget what 8 was for by sanabas (on 13. September 2025, 18:12) | 25 | 100 % |
| Rule of Thirds by sfushidahardy (on 15. October 2025, 17:19) | 26 | 100 % |
| Even Lighting by Jay Dyer (on 15. February 2023, 23:02) | 65 | 97 % |
| Build Your Own Killer: Criminal Mind by Playmaker6174 (on 3. March 2022, 18:07) | 42 | 100 % |
| Meidjuluk II (N=25) by glum_hippo (on 1. June 2023, 00:00) | 53 | 99 % |
| Full Circle by Qodec (on 22. September 2025, 16:15) | 62 | 97 % |
| Suguru Chaos Deconstruction: Sectioned Thermos by crispy16 (on 23. April 2022, 16:44) | 75 | 98 % |
| BYO Kropki Cages by mathpesto (on 10. December 2022, 02:33) | 76 | 99 % |
| Wichtelkalender 2013 - Oktober by pin7guin (on 1. October 2013, 00:00) | 27 | 91 % |
| LM 2016 - Spätfolgen: Sternenhimmel-Japanische Summen by ibag (on 15. August 2016, 20:13) | 42 | 99 % |
