(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 | |
|---|---|---|---|
 | Thermo Arrow Sudoku by Lizzy01 (on 27. April 2021, 17:15) | 24 |  95 % |
| O/E Little Killers by JoWovrin (on 4. June 2021, 22:50) | 22 | 96 % |
| Which Direction? by Lisztes (on 7. December 2021, 01:00) | 23 | 97 % |
| Perpetual Motion of Kind '0' (Sudoku 26) by Sumanta(ANU) (on 12. May 2022, 13:51) | 24 | 93 % |
| Copycat Collaboration by Scojo (on 28. June 2024, 13:38) | 56 | 99 % |
| Gemüse - Buchstabenrätsel / Letter Puzzle by DocLogic (on 16. January 2025, 15:09) | 20 | 96 % |
| Die Kryptos - S02E02: A 38 by tuace (on 16. March 2018, 15:10) | 43 | 96 % |
| Cage Scraper by glum_hippo (on 24. January 2021, 06:00) | 50 | 97 % |
| Classic Thermo Sudoku by Phistomefel (on 2. February 2021, 22:33) | 101 | 95 % |
| Intersections by Xenonetix (on 22. August 2023, 23:23) | 42 | 91 % |
| U-Bahn unter Hochhäusern (Teil 5) by Zzzyxas (on 31. March 2012, 16:17) | 61 | 99 % |
| Little Killer X Sudoku by Phistomefel (on 25. April 2020, 08:15) | 77 | 94 % |
| Liar Sudoku - Everything Is Wrogn by DiMono (on 18. September 2020, 19:23) | 94 | 99 % |
| Factor Attractor (Ratio Sudoku) by Volatility (on 28. July 2020, 03:10) | 46 | 96 % |
| Broken Ring by Lizzy01 (on 10. January 2021, 20:15) | 27 | 91 % |
| Parity Party XIV, "Avec cages" by glum_hippo (on 4. January 2021, 13:13) | 21 | 94 % |
| Pentominominous by emmettcito (on 22. May 2021, 18:51) | 21 | 99 % |
| Bent arrows by JoWovrin (on 19. June 2021, 13:20) | 43 | 96 % |
| Juosan Killer sudoku by udukos (on 25. October 2021, 05:54) | 44 | 97 % |
| SunSET Over The Pyramid by zegres (on 20. December 2021, 23:12) | 38 | 96 % |
