(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 | |
|---|---|---|---|
 | Addierter Überlappungssudoku III by Richard (on 14. May 2010, 12:00) | 82 |  96 % |
| Roller Coaster in Rätselhausen by Statistica (on 6. December 2016, 06:06) | 45 | 98 % |
| Indianapolis by ICHTUES (on 13. November 2022, 06:00) | 55 | 95 % |
| Kill-o-meter by Jreg (on 12. January 2023, 07:35) | 15 | 93 % |
| Count me out ! [Deconstruction] by Christounet (on 14. April 2023, 01:18) | 51 | 99 % |
| Denominators by AnalyticalNinja (on 29. January 2024, 00:30) | 31 | 96 % |
| How does this even work? - Odd/Even Killer sudoku by Mr.Menace (on 28. May 2024, 20:45) | 20 | 93 % |
| Mellow Mancala by heliopolix (on 13. July 2024, 00:00) | 16 | 91 % |
| Wichtels (später) Rätselsommer 2024 (10): Yingu Jam by wichtel (on 3. October 2024, 20:23) | 16 | 92 % |
| Invasion! by Sotehr (on 27. October 2024, 00:00) | 16 | 95 % |
| Heated Entropy by Mad-Tyas (on 14. December 2021, 00:10) | 70 | 97 % |
| Sudoku Variants Series (385) - Consecutive Sums Sudoku by Richard (on 21. September 2022, 02:00) | 88 | 98 % |
| Rundweg auf dem Würfel by flooser (on 3. September 2009, 12:18) | 77 | 96 % |
| Inner Skyscrapers by tesseralis (on 30. September 2022, 23:08) | 71 | 98 % |
| Happy Birthday, marcmees! by ibag (on 15. August 2020, 00:00) | 18 | 100 % |
| Killer Sudoku #1 (‘The Portal’) by PixelPlucker (on 12. November 2020, 09:48) | 25 | 91 % |
| Mysterious Couple by sujoyku (on 19. November 2022, 13:20) | 23 | 97 % |
| Recombination by Jay Dyer (on 11. October 2021, 20:05) | 27 | 97 % |
| Pentomino Sandwich by RockyRoer (on 9. January 2023, 23:42) | 22 | 98 % |
| Chinmax Skystrappers by ChinStrap (on 30. May 2025, 18:04) | 49 | 93 % |
