(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 | |
|---|---|---|---|
 | Japanischer Summen-Rundweg 2358 (1) by Uhu (on 2. May 2017, 21:10) | 54 |  98 % |
| OSTERN - Buchstabenrätsel by DocLogic (on 31. March 2020, 22:50) | 34 | 92 % |
| Two Sum Sudoku Finale - With Only One Numerical Clue! by ProwlingTiger (on 1. May 2020, 21:35) | 45 | 98 % |
| Galaxy Killer #2 by Phistomefel (on 18. May 2020, 19:10) | 60 | 93 % |
| Wichtel 2019 (2): Bier oder Wein by wichtel (on 29. June 2020, 19:20) | 32 | 97 % |
| Cryptic Battlefield Sudoku by Jesper (on 18. July 2020, 19:57) | 22 | 99 % |
| Cosmology by Bobuardo da Vinci (on 6. August 2020, 07:36) | 24 | 99 % |
| Negative Sandwich Sudoku by clover (on 7. August 2020, 19:15) | 11 | 90 % |
| Teams Sudoku - Counts or Sums? by stephane.bura (on 17. August 2020, 20:00) | 12 | 95 % |
| Space Oddity - Irregular Parity Galaxy Killer Sudoku by Yohann (on 20. August 2020, 11:18) | 23 | 98 % |
| ¿? Mystery products ¿? by Qodec (on 28. August 2020, 16:32) | 22 | 97 % |
| Battlefield Sandwich Sudoku - Fight For Lunch by DiMono (on 7. September 2020, 18:16) | 23 | 91 % |
| Killer Python by jacksongriggs (on 8. September 2020, 05:29) | 13 | 98 % |
| Compass Sudoku by stephane.bura (on 5. November 2020, 20:00) | 50 | 99 % |
| Pencil puzzle sudoku hybrid series #1 - Look-air sudoku by Aspartagcus (on 28. October 2020, 11:11) | 13 | 90 % |
| Summenbild-Rundwegrätsel (2) by Uhu (on 22. November 2020, 19:13) | 26 | 97 % |
| Masyu Loop Sudoku by Jesper (on 10. November 2020, 09:49) | 53 | 97 % |
| Antiknight killer - Barcelona Floor Tile by Ferranrojas (on 12. November 2020, 01:32) | 22 | 96 % |
| Mystery Sandwich Sudoku by cdwg2000 (on 11. January 2021, 23:11) | 13 | 95 % |
| The Python (Palindrome) by ICHTUES (on 15. November 2020, 06:00) | 30 | 95 % |
