(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 | |
|---|---|---|---|
 | five pointed stars, five lettered cells (Pentominous/Star Battle) by Nell Gwyn (on 18. February 2025, 20:18) | 26 |  100 % |
| Killeriana: Ungleichungskiller by Pyrrhon (on 8. October 2009, 14:35) | 91 | 96 % |
| Polka Dot by PotatoHead21 (on 26. March 2023, 18:47) | 107 | 94 % |
| Adventskalender 2020, Türchen 7 - Twilight-Tapa by Zzzyxas (on 7. December 2020, 07:00) | 79 | 98 % |
| Sudokulike [DFoW] by Nurator (on 6. March 2025, 11:58) | 158 | 96 % |
| HALLOWEEN - gruseliges Buchstabenrätsel by DocLogic (on 24. October 2020, 13:13) | 41 | 99 % |
| ABC-Box Skyscraper - From A Window by DiMono (on 18. August 2021, 18:58) | 40 | 99 % |
| Times Square by grkles (on 5. November 2021, 16:56) | 38 | 94 % |
| Very old burger (German Whisper + Kropki + Antiknight Sudoku) by Sktx (on 17. September 2022, 16:50) | 57 | 95 % |
| Nine Bent Arrows, One Straight by rmahus (on 14. March 2023, 10:00) | 47 | 97 % |
| City of Skyscrapers by Kitty Trouble (on 5. November 2023, 14:45) | 40 | 96 % |
| Hooked (Region Sum Lines) by Florian Wortmann (on 11. August 2024, 12:24) | 192 | 97 % |
| Killer Gossip by Kaktuslav (on 6. October 2025, 08:00) | 42 | 94 % |
| Anti-Knight Killer Sudoku #2 by udukos (on 2. March 2021, 10:19) | 67 | 95 % |
| Sudoku Variants Series (245) - Counting Neighbours Sudoku by Richard (on 4. December 2018, 00:00) | 109 | 93 % |
| Sudoku Variants Series (284) - Isolation Killer Sudoku by Richard (on 2. September 2020, 00:00) | 105 | 96 % |
| Pocket Sandwich Sudoku by Genomico (on 1. November 2020, 20:25) | 16 | 92 % |
| The Whirlpool by LucyAudrin (on 7. January 2021, 23:08) | 25 | 90 % |
| Boba by grkles (on 20. April 2021, 18:28) | 30 | 94 % |
| Jigsaw by PotatoHead21 (on 20. June 2021, 19:54) | 22 | 90 % |
