(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 | |
|---|---|---|---|
 | Double Arrow Melt by Black_Doom (on 8. May 2024, 19:06) | 39 |  95 % |
| Double Dragon 2 by Nordy (on 4. May 2023, 23:10) | 40 | 95 % |
| Counter-Clockwise Chaos Construction by sfushidahardy (on 8. November 2024, 04:32) | 70 | 98 % |
| Fillomino sudoku by Aspartagcus (on 26. March 2024, 13:39) | 116 | 95 % |
| 1001-Nacht-Rundweg by ibag (on 4. November 2013, 00:00) | 32 | 97 % |
| 10-in-9 calcudoku #1 by Nylimb (on 27. January 2020, 10:04) | 34 | 97 % |
| EUROPA - Buchstabenpyramide / letter pyramid by DocLogic (on 17. July 2020, 17:07) | 35 | 95 % |
| Crossbar by purpl (on 12. August 2021, 07:12) | 36 | 94 % |
| Louisville by ICHTUES (on 6. February 2022, 06:00) | 36 | 95 % |
| Skyscraper Slingshot Sudoku #2 by Piatato (on 1. March 2023, 23:49) | 33 | 99 % |
| Little Killer X Sudoku by Phistomefel (on 25. April 2020, 08:15) | 85 | 94 % |
| Cross Stitching 101 (Equalines Sudoku) by Sktx (on 1. November 2022, 15:51) | 34 | 91 % |
| Meander (Slitherlink/Japanese sums sudoku) by dumediat (on 11. August 2023, 12:25) | 35 | 93 % |
| Productivity by juggler (on 19. December 2024, 20:34) | 35 | 94 % |
| NYPD by phil_the (on 29. May 2025, 13:01) | 42 | 99 % |
| Tenable by jwsinclair (on 20. June 2025, 21:59) | 36 | 94 % |
| Handshake (Arrow Sudoku) by Niverio (on 15. July 2022, 01:08) | 106 | 98 % |
| Little Big Killer Sudoku (updated) by Shinya (on 16. June 2020, 08:00) | 37 | 98 % |
| Neighbor Feud by Piatato (on 29. May 2021, 15:58) | 36 | 95 % |
| Roller Coaster mit Extras 24 by Uhu (on 5. October 2021, 14:00) | 31 | 99 % |
