(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 | |
|---|---|---|---|
 | Good and Plenty by Blobz (on 22. October 2025, 16:00) | 183 |  97 % |
| Japanische Summen - Krypto by ibag (on 22. July 2012, 09:20) | 83 | 99 % |
| Killer Sudoku - Progress City by DiMono (on 14. September 2020, 01:27) | 70 | 97 % |
| Two Strings by zegres (on 21. July 2022, 04:38) | 125 | 98 % |
| Arrows Dilemma by Prof.Dori (on 14. August 2023, 16:02) | 56 | 93 % |
| 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 % |
| Kerzen 4 by usp (on 26. January 2015, 00:00) | 49 | 95 % |
| Killer Sudoku (WSC 2019 Leftover) by Realshaggy (on 9. September 2019, 21:23) | 103 | 95 % |
| 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) | 49 | 98 % |
| Kakuro ('Plaza') by PixelPlucker (on 17. June 2021, 05:41) | 75 | 95 % |
| My cup of tea - arrow/killer sudoku by Mr.Menace (on 23. April 2021, 22:07) | 40 | 97 % |
| Toothbrushes by krangune (on 8. May 2022, 12:49) | 37 | 97 % |
| ADVENTSKALENDER - Buchstabenrätsel / Letter Puzzle by DocLogic (on 20. December 2022, 14:35) | 34 | 97 % |
| S-Thermo by Prof.Dori (on 11. May 2023, 12:42) | 38 | 93 % |
| Mislabeled Killers by CaptZebraCakes (on 27. June 2024, 04:35) | 144 | 98 % |
| City of Nomura (Zipper Lines/Skyscraper) by Tyrgannus (on 27. July 2025, 03:21) | 31 | 92 % |
| Nonoknights V by Villse (on 24. May 2026, 15:23) | 83 | 95 % |
| Sum Set Sudoku by Genomico (on 11. May 2021, 00:00) | 26 | 99 % |
