(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 | |
|---|---|---|---|
 | Cliff Diver (Rossini Killer Sudoku) by clover (on 30. April 2026, 21:53) | 31 |  95 % |
| There's Sum-thing In The Shadows (with sujoyku) by ChinStrap (on 2. May 2025, 18:05) | 112 | 97 % |
| Adaptation by mathpesto (on 18. January 2025, 17:49) | 82 | 98 % |
| Zodiac Project: Cage Decoder by sujoyku (on 12. June 2024, 23:06) | 119 | 95 % |
| Adventskalender-ABCtje by StefanSch (on 30. November 2012, 00:00) | 35 | 91 % |
| Reversi by Wuschel (on 5. November 2023, 21:18) | 77 | 96 % |
| jolly green giant, his arms folded by mellowrobinson (on 11. November 2025, 03:21) | 37 | 99 % |
| One Fish, Two Fish by Blobz (on 13. December 2025, 16:00) | 91 | 95 % |
| Japanische Summen gerade - ungerade by ibag (on 1. August 2012, 22:10) | 84 | 99 % |
| Imprisoned (Killer Rooms Sudoku) by Agent (on 2. July 2022, 09:00) | 90 | 99 % |
| 2many arrows spoil the box by tesseralis (on 27. August 2022, 07:31) | 101 | 96 % |
| Cross Whispers by Fool on Hill (on 1. June 2023, 15:08) | 62 | 93 % |
| This or That - Killer Sudoku by Mr.Menace (on 31. August 2024, 19:22) | 67 | 92 % |
| Anti-Knight Thermos 3 by Jeet Sampat (on 7. October 2025, 05:57) | 108 | 98 % |
| Schlingerpfad 11x17 by adam001 (on 20. September 2012, 13:56) | 19 | 94 % |
| Toroidal Snake - etwas verkürzt by lupo (on 4. February 2018, 23:53) | 21 | 94 % |
| Roller Coaster U-Bahn by Zzzyxas (on 22. August 2019, 18:25) | 58 | 99 % |
| Three Arrows by Onion Suit (on 5. May 2021, 02:31) | 24 | 94 % |
| Wave Sudoku by Vebby (on 26. May 2021, 19:06) | 18 | 95 % |
| Diamonds by abed hawila (on 6. June 2021, 17:16) | 20 | 96 % |
