(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 | |
|---|---|---|---|
 | Yozzy by zetamath (on 6. May 2024, 02:28) | 31 |  95 % |
| Sorted Subway by KNT (on 22. July 2024, 07:21) | 29 | 100 % |
| Zoom Out by Myxo (on 30. July 2024, 12:22) | 89 | 99 % |
| Colossal Cave Sudoku by tesseralis (on 28. October 2022, 03:02) | 56 | 99 % |
| Pentomino Schleifen (NFF) by Richard (on 8. October 2010, 12:00) | 28 | 92 % |
| Wichtel 2016 (12 und Schluss): Unterirdische Katakomben mit Kerzenbeleuchtung by wichtel (on 12. October 2017, 21:01) | 24 | 99 % |
| Invisible Cages by Big Tiger (on 25. March 2021, 10:42) | 26 | 100 % |
| Chained killer sudoku no. 3 by Shinya (on 23. August 2021, 22:33) | 22 | 99 % |
| Adventskalender 2023, Türchen 15 - Knapp daneben U-Bahn by Zzzyxas (on 15. December 2023, 07:00) | 24 | 93 % |
| Stroopwafel by pieguy (on 19. October 2023, 23:13) | 25 | 92 % |
| Adventskalender 2023, Türchen 9 - Glashochhäuser by Zzzyxas (on 9. December 2023, 07:00) | 46 | 99 % |
| Inner Square Diagonals by Phistomefel (on 12. August 2024, 13:31) | 73 | 97 % |
| Japanische Bahnhöfe, Teil 2 by pirx (on 27. May 2020, 13:00) | 23 | 100 % |
| Heterochromia (Killer Sudoku) by emmettcito (on 30. March 2021, 00:42) | 52 | 96 % |
| Ambiguity (X-Sums/Numbered Rooms) by udukos (on 5. July 2022, 13:25) | 63 | 97 % |
| Glyphs #5 by damasosos92 (on 23. February 2023, 23:55) | 47 | 96 % |
| Leakage by Testarossa (on 21. January 2023, 20:10) | 68 | 100 % |
| Wichtel 2019 (11 und Schluss): Es soll nicht langweilig werden! by wichtel (on 6. November 2020, 20:01) | 17 | 100 % |
| CTC Tribute Arrow Sudoku by Lizzy01 (on 6. June 2021, 20:37) | 24 | 94 % |
| DEATH (collaboration) by grkles (on 4. January 2022, 22:20) | 39 | 99 % |
