(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 | |
|---|---|---|---|
 | Kakuro Series 4: Kakuro (Gapped) by Puzzle_Maestro (on 12. May 2020, 13:00) | 58 |  97 % |
| Nurikabe by wooferzfg (on 5. April 2025, 05:15) | 113 | 96 % |
| Arrows And Dots by Jeet Sampat (on 14. March 2022, 03:18) | 56 | 98 % |
| 2:1 Architecture by Scruffamudda (on 16. November 2024, 06:11) | 60 | 97 % |
| Blue Arrow by Kaktuslav (on 10. February 2025, 20:35) | 63 | 96 % |
| The 27 Club (with sujoyku) by mellowrobinson (on 7. July 2025, 05:16) | 119 | 98 % |
| Anti-Knight Killer Sudoku #2 by Phistomefel (on 31. October 2020, 09:40) | 123 | 92 % |
| Compass Sudoku by stephane.bura (on 5. November 2020, 20:00) | 55 | 99 % |
| In or Out? (Between Lockout Ambiguity) by tallcat (on 1. October 2021, 16:33) | 50 | 97 % |
| Wichtel 2015 (3): Maschinelle Synthese by wichtel (on 24. March 2016, 10:25) | 48 | 98 % |
| Hieroglyph (Entropic Killer) by tallcat (on 15. October 2022, 18:02) | 57 | 94 % |
| Euler Knights by Raumplaner (on 6. April 2023, 17:34) | 51 | 96 % |
| Inner Peas by SamuPiano (on 17. July 2024, 15:44) | 57 | 98 % |
| Zeltplatz im Zauberwald by SilBer (on 21. November 2010, 20:33) | 50 | 96 % |
| Killer Sanduhr by tuace (on 3. November 2013, 04:30) | 47 | 97 % |
| 10-in-9 sandwich sudoku by Nylimb (on 26. March 2020, 10:16) | 50 | 98 % |
| Xtravaganza (S-Cell XV Sudoku X) by tallcat (on 26. October 2022, 09:00) | 49 | 98 % |
| Geometry Exam #3 by Blashyrkh (on 7. August 2023, 19:46) | 58 | 94 % |
| Hidden Pentominoes Killer/Little Killer Sudoku by MagnusJosefsson (on 6. May 2021, 13:07) | 47 | 98 % |
| Canal View Japanese Sums by Agent (on 28. May 2024, 09:00) | 51 | 99 % |
