(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 | |
|---|---|---|---|
 | Sea Skeleton [Classic Sudoku] by wisty (on 25. October 2022, 20:28) | 55 |  95 % |
| Modunacci by Goofy (on 16. February 2023, 00:02) | 13 | 90 % |
| A Land of Hidden Serpents by oxjphs (on 5. July 2023, 00:22) | 25 | 90 % |
| Instructionless by dennischen (on 29. July 2023, 04:44) | 24 | 94 % |
| To The Nines by arbitrary (on 9. October 2023, 23:05) | 12 | 93 % |
| Production Lines by Mr Toffee (on 5. June 2024, 17:35) | 13 | 95 % |
| Sleeper Cells by Bearded Fool (on 30. August 2024, 12:00) | 32 | 91 % |
| [TSL][S1T1] Per-Pea-Tuate by SamuPiano (on 17. October 2024, 15:44) | 13 | 90 % |
| Chaos Control by Scojo (on 15. April 2023, 01:59) | 54 | 94 % |
| Think you can break in? (FOW) by antiknight (on 17. August 2024, 02:06) | 107 | 92 % |
| Killer Sudoku by Greg (on 14. June 2020, 21:04) | 41 | 92 % |
| Arrows And Renban Lines by Jeet Sampat (on 11. November 2022, 00:32) | 42 | 96 % |
| Switch-O-Renban by Ridhwan (on 5. May 2024, 11:06) | 38 | 95 % |
| Suguru Chaos Deconstruction by mathpesto (on 12. February 2022, 23:45) | 158 | 99 % |
| Tauschpfad (2) by BFaw (on 27. August 2011, 13:20) | 29 | 92 % |
| CtC-Tribute-Thermo-Sudoku by olima (on 15. August 2020, 23:42) | 61 | 91 % |
| Portal Killer by crispy16 (on 11. June 2022, 04:29) | 28 | 96 % |
| Slingin' Sammies by mnasti2 (on 20. January 2023, 10:33) | 26 | 99 % |
| This is it. I've done it. by EricRathbun (on 23. April 2023, 00:19) | 55 | 97 % |
| Equal Sum Arrows by Sumanta(ANU) (on 7. June 2023, 11:21) | 29 | 93 % |
