(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 | |
|---|---|---|---|
 | Radical Region Sum Loop by yttrio (on 17. November 2023, 21:25) | 58 |  95 % |
| Pixy Stix by thoughtbyte (on 18. April 2024, 20:32) | 51 | 94 % |
| ▚▚ Summing-Zipper-Loop ▞▞ by ElChiglia (on 2. March 2024, 07:15) | 31 | 93 % |
| ← Find-the-Whisper-Loop → by ElChiglia (on 23. March 2024, 07:15) | 34 | 91 % |
| Kropki XV Puzzle (Oops! No clues!) by RockyRoer (on 5. February 2021, 11:56) | 47 | 95 % |
| OOO OOO by Joseph nehme (on 20. November 2021, 08:07) | 50 | 94 % |
| Production Line by starwarigami (on 12. August 2022, 11:41) | 50 | 94 % |
| Grid Your Lions by cristophermoore (on 16. September 2023, 23:53) | 53 | 91 % |
| Killer Sudoku: Variety (revamped) by Playmaker6174 (on 26. December 2023, 09:00) | 55 | 94 % |
| Samurai Sandwiches by mathpesto (on 28. December 2022, 17:34) | 63 | 95 % |
| The Knight and the Knave (Legit/Liar Sudoku) by mathpesto (on 16. August 2022, 23:13) | 75 | 97 % |
| Half the Digits (Killer) by Cane_Puzzles (on 24. May 2024, 18:06) | 162 | 96 % |
| Balance = Entropy by JeremyDover (on 12. February 2022, 23:59) | 108 | 98 % |
| Chained Killer Sudoku no. 2 by Shinya (on 21. February 2020, 22:48) | 32 | 95 % |
| My first Sudoku by Selsted (on 12. July 2020, 18:42) | 30 | 91 % |
| Kropki Placement Sudoku #2 by udukos (on 24. November 2020, 10:27) | 25 | 93 % |
| Cryptic Nurikabe Python by udukos (on 2. January 2021, 16:08) | 16 | 98 % |
| Feeling Left Out by RockyRoer (on 10. February 2021, 11:57) | 18 | 94 % |
| It's Gonna Be a Long Knight by cam (on 16. February 2021, 07:04) | 51 | 98 % |
| Battleships! - Sudoku by JeffWajes (on 28. March 2021, 06:13) | 33 | 97 % |
