(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 | |
|---|---|---|---|
 | Two Strings by zegres (on 21. July 2022, 04:38) | 125 |  98 % |
| Circles and Sets by JeffWajes (on 22. January 2024, 02:21) | 110 | 97 % |
| Happy birthday, pin7guin by ibag (on 6. September 2011, 00:00) | 43 | 92 % |
| High Winds (Arrow Sudoku) by Agent (on 16. May 2021, 09:00) | 42 | 94 % |
| Double Duty | Zweifache Zahlenbedeutung by olima (on 21. February 2023, 22:52) | 48 | 98 % |
| My cup of tea - arrow/killer sudoku by Mr.Menace (on 23. April 2021, 22:07) | 39 | 97 % |
| Castle Wall / Masyu Liars by Agent (on 24. January 2023, 09:00) | 39 | 99 % |
| City of Nomura (Zipper Lines/Skyscraper) by Tyrgannus (on 27. July 2025, 03:21) | 31 | 92 % |
| More Drunken Knights by Blobz (on 9. September 2022, 16:00) | 106 | 96 % |
| Sum Set Sudoku by Genomico (on 11. May 2021, 00:00) | 26 | 99 % |
| Beep Beep (Killer/German Whispers/Renban/Between Lines) by dumediat (on 18. May 2022, 23:28) | 31 | 93 % |
| Parity Sum Lines Sudoku by Agent (on 16. August 2022, 09:00) | 52 | 96 % |
| Masyudoku (Masyu/Latin Square/Loop Sums/Ambiguity) by dumediat (on 30. September 2022, 02:35) | 22 | 95 % |
| Take U-Turns by Black_Doom (on 20. March 2024, 04:35) | 51 | 96 % |
| Evolution by grkles (on 10. March 2023, 12:16) | 76 | 91 % |
| Rätselwochenende: Table for Four - Easy as Pentomino by uvo (on 26. November 2014, 16:40) | 39 | 93 % |
| Killomino by josh_johnson (on 9. July 2022, 04:16) | 48 | 93 % |
| Pull-ups by Morisenseiisgod (on 5. January 2026, 13:16) | 41 | 94 % |
| Mislabeled Killers by CaptZebraCakes (on 27. June 2024, 04:35) | 141 | 98 % |
| Numbered Walls by Niverio (on 21. July 2022, 23:57) | 72 | 100 % |
