(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 | |
|---|---|---|---|
 | Killer Cave by udukos (on 7. October 2021, 06:12) | 58 |  100 % |
| Quadstruction by Oddlyeven (on 7. May 2023, 21:25) | 58 | 98 % |
| Ambiguity (X-Sums/Numbered Rooms) by udukos (on 5. July 2022, 13:25) | 67 | 97 % |
| 4 Corners Killer Sudoku by Strosahl (on 30. September 2020, 17:20) | 30 | 93 % |
| Six-pack Linked Sudokus #10 - Sums by Genomico (on 30. September 2022, 16:30) | 27 | 100 % |
| E ∩ tropy (Killer, Entropy Theme) by Crusader175 (on 20. May 2023, 16:00) | 30 | 94 % |
| Killer Shikoku by the_cogito (on 9. March 2022, 00:16) | 57 | 98 % |
| Bouquet by Myxo (on 15. September 2023, 10:41) | 87 | 98 % |
| Kropkiflotte auf hoher See II by Luigi (on 30. October 2014, 13:51) | 14 | 93 % |
| Magic Sandwich Sudoku by Madmahogany (on 10. May 2020, 20:22) | 25 | 99 % |
| Mysterious Samurai (Hard Ver. of Sudoku Challenge 2020) by Kwaka (on 12. September 2020, 23:40) | 16 | 93 % |
| NonoSums by Mark Sweep (on 4. October 2020, 20:41) | 15 | 98 % |
| Cave Akari by Mark Sweep (on 4. December 2020, 10:00) | 54 | 99 % |
| Little Killer by Strosahl (on 7. April 2021, 05:36) | 27 | 99 % |
| Kropkiominos by zetamath (on 30. May 2021, 00:17) | 35 | 97 % |
| Mosaic cogs [Extended diagonal XV - virtual sudoku] by SimplePurpleFrog (on 2. November 2021, 04:05) | 23 | 100 % |
| Recurring Nightmares by Jay Dyer (on 16. October 2022, 01:00) | 39 | 97 % |
| Double Rank by Andrewsarchus (on 5. November 2022, 17:39) | 13 | 98 % |
| Killer Kropki Cages sequel by Ryx (on 28. March 2023, 06:45) | 13 | 91 % |
| Ban it twice! (Yin Yang, Renban) by Paletron (on 17. August 2023, 22:41) | 15 | 98 % |
