(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 | |
|---|---|---|---|
 | SPION-AGENT-KUNDSCHAFTER Buchstabenrätsel by DocLogic (on 16. March 2021, 14:14) | 38 |  98 % |
| Until Ten (10-lines, parity mirror) by the_cogito (on 20. February 2023, 15:28) | 41 | 97 % |
| Extenban YYSL by Blobz (on 25. December 2023, 16:00) | 101 | 98 % |
| Discontinuity? by JayForty (on 2. February 2024, 16:38) | 92 | 96 % |
| Die Traumaufzeichnung by berni (on 28. May 2009, 14:38) | 45 | 91 % |
| Pike Soup (Kropki Pairs) by Florian Wortmann (on 13. October 2021, 18:44) | 55 | 90 % |
| Tesla Coil (German Whispers + Odd/Even) by purpl (on 3. November 2021, 19:27) | 53 | 93 % |
| Stammtisch-Teamrätsel mit Portalen by CJK (on 12. August 2023, 19:08) | 46 | 99 % |
| ♫ Slitherlink take me home ♫ by Phistomefel (on 1. April 2022, 01:04) | 56 | 99 % |
| Odd/Even Sandwich Sudoku by Piatato (on 2. August 2021, 13:33) | 50 | 92 % |
| Quad sums sudoku by udukos (on 17. August 2021, 18:07) | 52 | 95 % |
| Pile of 15 (Killer Sudoku) by Cane_Puzzles (on 2. December 2022, 15:51) | 69 | 94 % |
| Yin Yang Position Sums Sudoku by Jesper (on 3. November 2022, 19:17) | 75 | 97 % |
| Killer Sudoku (WSC 2019 Leftover) by Realshaggy (on 9. September 2019, 21:23) | 101 | 95 % |
| Different Differences by marty_sears (on 21. October 2023, 19:43) | 129 | 94 % |
| Krypt-Rundweg verkehrt by lupo (on 8. July 2009, 14:35) | 25 | 96 % |
| Japanische Summen auf Antimagneten(2) by r45 (on 9. July 2013, 09:07) | 67 | 99 % |
| ABC-Box mit Buchstabensalat-Kern mit Hochhaus-Kern by ibag (on 14. July 2013, 23:18) | 64 | 99 % |
| Knapp-daneben-Kryptos (6): Japanische Summen by ibag (on 2. February 2014, 21:29) | 58 | 98 % |
| LM 2017 Reste: Hakyuu-Hitori by pwahs (on 6. April 2017, 10:00) | 39 | 94 % |
