(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 | |
|---|---|---|---|
 | Twin Killer Sudoku V by Richard (on 16. March 2012, 12:00) | 71 |  94 % |
| Fat X (little killer sudoku) by Aspartagcus (on 9. March 2023, 18:46) | 91 | 95 % |
| Twin chaos sudoku by Richard (on 21. October 2009, 21:48) | 110 | 93 % |
| U-Bahn unter Hochhäusern (Teil 9) by Zzzyxas (on 5. May 2012, 18:21) | 52 | 98 % |
| Schlingerpfad 11x17 by adam001 (on 20. September 2012, 13:56) | 18 | 93 % |
| Anti-sudoku puzzle #3 by Nylimb (on 17. February 2020, 06:56) | 36 | 94 % |
| Adventskalender 2020, Türchen 7 - Twilight-Tapa by Zzzyxas (on 7. December 2020, 07:00) | 73 | 98 % |
| Little Thermo Sudoku by Alexander Rappa (on 16. June 2020, 16:15) | 33 | 96 % |
| Invisible Slingshot Killers and Silent Killers Sudoku by stephane.bura (on 22. August 2020, 10:44) | 15 | 98 % |
| Even Couples Killer Sudoku by Quarterthru (on 3. September 2020, 12:00) | 25 | 96 % |
| Mini Killers by Aspartagcus (on 6. September 2020, 20:30) | 27 | 96 % |
| Yajikazu Sudoku by Madmahogany (on 9. September 2020, 14:21) | 49 | 96 % |
| Basket Case by cam (on 30. September 2020, 01:34) | 17 | 94 % |
| Prime sum snake sudoku by Nylimb (on 27. November 2020, 07:54) | 20 | 97 % |
| The Negative Diagonal by Lisztes (on 1. December 2020, 01:00) | 16 | 92 % |
| ThermoXidil by fritzdis (on 17. March 2021, 04:48) | 44 | 94 % |
| Little Parity Party Sudoku by MagnusJosefsson (on 21. March 2021, 00:32) | 21 | 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 % |
