(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 | |
|---|---|---|---|
 | Identity Crisis by DubiousMobius (on 5. January 2025, 03:16) | 19 |  95 % |
| 2 Corners by apete (on 1. November 2025, 00:30) | 17 | 92 % |
| Clockwise by apete (on 26. November 2025, 23:02) | 29 | 90 % |
| Systematic Traffic by MathGuy_12 (on 30. January 2026, 04:33) | 27 | 93 % |
 | Memories of a Far Off Land • 遠い国の思い出 by juggler (on 10. June 2026, 20:37) | 74 | 97 % |
| Mind the Gap (Arrow X Sudoku) by tallcat (on 28. April 2021, 02:08) | 46 | 94 % |
| Entropy and Whispers (Sudoku29) by Sumanta(ANU) (on 16. June 2022, 14:34) | 51 | 94 % |
| Bonds (Killer + Arrow) by Playmaker6174 (on 18. January 2026, 05:00) | 143 | 97 % |
| Es war einmal eine geheime Schrift by berni (on 1. November 2008, 15:56) | 78 | 92 % |
| Neulich beim Stammtisch Ruhrgebiet by berni (on 15. December 2013, 15:28) | 46 | 97 % |
| Broken Slitherlink by ahaupt (on 21. May 2020, 11:02) | 53 | 99 % |
| Circle Squared by Ridhwan (on 2. January 2024, 03:27) | 32 | 96 % |
| Gravitation by Niverio (on 3. July 2024, 19:49) | 25 | 92 % |
| Homebound Sandwich Sudoku by Sebastian Losch (on 25. April 2020, 21:37) | 19 | 94 % |
| Gossiping Queens on 7x7 Torus by SudokuExplorer (on 10. September 2020, 17:44) | 17 | 93 % |
| Triplet Sums by Realshaggy (on 27. January 2021, 23:59) | 30 | 93 % |
| The BremSter Thermo Conundrum by Zombie Hunter (on 16. September 2021, 00:25) | 20 | 92 % |
| Contiguous by grkles (on 21. May 2022, 13:07) | 58 | 92 % |
| Prime Directive by DiMono (on 15. April 2023, 15:35) | 16 | 92 % |
| Modular Loop by SamuPiano (on 8. November 2023, 05:29) | 14 | 94 % |
