(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 | |
|---|---|---|---|
 | Prime sum snake sudoku by Nylimb (on 27. November 2020, 07:54) | 21 |  97 % |
| The Negative Diagonal by Lisztes (on 1. December 2020, 01:00) | 18 | 92 % |
| Little Parity Party Sudoku by MagnusJosefsson (on 21. March 2021, 00:32) | 22 | 96 % |
| Ultimate Mashup by Joseph nehme (on 3. April 2021, 09:31) | 37 | 97 % |
| Übungsrätsel LM-Quali 2021: Pentopia-Myopia II by lupo (on 13. April 2021, 20:21) | 22 | 97 % |
| Mystery Kropki Sudoku #2 by Cane_Puzzles (on 13. April 2021, 15:30) | 28 | 93 % |
| Cracked by abed hawila (on 20. April 2021, 01:54) | 13 | 100 % |
| Killer Elephant by SlowLarry (on 25. May 2021, 12:26) | 33 | 93 % |
| Parity Party Renban Sudoku ('Party Bot') by PixelPlucker (on 31. May 2021, 16:05) | 17 | 95 % |
| A Very Odd Killer by Niverio (on 9. June 2021, 17:55) | 58 | 99 % |
| The 13th Nightmare by Nahileon (on 25. August 2021, 19:08) | 38 | 90 % |
| Think Outside the Cage by cristophermoore (on 22. September 2021, 03:35) | 41 | 98 % |
| Kropki-Arrow Party by abed hawila (on 6. November 2021, 09:40) | 42 | 97 % |
| Battle With The Archers 22: Double Speculations by Playmaker6174 (on 26. November 2021, 10:06) | 24 | 93 % |
| Close Friends by mathpesto (on 2. December 2021, 21:43) | 32 | 95 % |
| Black Jack by Andrewsarchus (on 5. December 2021, 07:02) | 19 | 97 % |
| Schrödinger's Dots by starwarigami (on 18. December 2021, 02:34) | 54 | 99 % |
| Oreo by the_cogito (on 16. January 2022, 18:07) | 13 | 96 % |
| Tightly Packed by Cane_Puzzles (on 3. February 2022, 12:01) | 91 | 96 % |
| 2-knight by fritzdis (on 21. March 2022, 20:40) | 51 | 91 % |
