(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 | |
|---|---|---|---|
 | Butterfly Effect (Renban Between Lines Sudoku) by Phistomefel (on 6. February 2023, 22:33) | 155 |  98 % |
| Zwei Rundwege aufeinander by Micha (on 31. December 2010, 16:04) | 45 | 98 % |
| OutsideTheUsula by Palfly Kampling (on 4. July 2023, 01:47) | 49 | 91 % |
| This or That - Killer Sudoku by Mr.Menace (on 31. August 2024, 19:22) | 52 | 91 % |
| Noch ein runder Rundweg 2 by Calavera (on 11. August 2009, 18:09) | 40 | 98 % |
| Spring Sudoku（1） by cdwg2000 (on 9. September 2020, 15:51) | 45 | 95 % |
| Squiggle by Lisztes (on 11. April 2021, 01:00) | 27 | 96 % |
| Ghost Digit by jwsinclair (on 15. October 2021, 19:25) | 26 | 97 % |
| The 28th Party (CTC Secret Santa 2021) by Niverio (on 29. December 2021, 00:11) | 69 | 97 % |
| Archer Towers by Angelo (on 12. May 2022, 20:09) | 19 | 94 % |
| Schrödinger's Leopard by tesseralis (on 12. July 2022, 11:52) | 40 | 99 % |
| Infancy by Myxo (on 14. November 2022, 14:27) | 105 | 97 % |
| Ocular by Maxentius (on 19. December 2022, 21:24) | 25 | 93 % |
| MP: Region Sum Lines Fillomino by Myxo (on 28. January 2023, 14:28) | 39 | 98 % |
| Strawberry Fields by cristophermoore (on 18. April 2023, 02:31) | 41 | 94 % |
| Hardened Points by arbitrary (on 20. December 2023, 23:31) | 19 | 94 % |
| Zany Zipper Snake by starwarigami (on 15. February 2024, 00:00) | 26 | 92 % |
| Breach by vitaminz (on 16. May 2024, 00:15) | 20 | 97 % |
| Heat Intensity by Calesch (on 13. August 2024, 05:09) | 19 | 94 % |
| Staggered by the_cogito (on 26. November 2021, 03:31) | 53 | 97 % |
