(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 | |
|---|---|---|---|
 | Die Traumaufzeichnung by berni (on 28. May 2009, 14:38) | 45 |  91 % |
| 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) | 47 | 99 % |
| ♫ Slitherlink take me home ♫ by Phistomefel (on 1. April 2022, 01:04) | 57 | 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 % |
| 4x4 Arrow XV Sudokus by SudokuExplorer (on 1. April 2022, 08:00) | 47 | 94 % |
| Different Differences by marty_sears (on 21. October 2023, 19:43) | 133 | 94 % |
| Chaos Construction: Glow by Xenonetix (on 7. February 2022, 01:00) | 66 | 94 % |
| Undec-ided by SirSchmoopy (on 11. April 2022, 00:06) | 77 | 98 % |
| 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) | 76 | 97 % |
| 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 % |
| LM Crossword by rimodech (on 26. April 2020, 21:16) | 20 | 95 % |
| Half The Killer I Used To Be by Djmelee3000 (on 1. September 2020, 00:17) | 34 | 93 % |
| X-Sums Sandwich Sudoku by RobK (on 12. October 2020, 09:37) | 13 | 95 % |
