(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 | |
|---|---|---|---|
 | BYO RSL by mathpesto (on 5. November 2023, 15:55) | 31 |  94 % |
| Mayan Ruins (Run-on Renban) by riffclown (on 20. November 2023, 13:18) | 31 | 94 % |
| Cutting Corners (by jovi_al & Qodec) by Qodec (on 4. September 2021, 10:44) | 52 | 97 % |
| Roller Coaster mit Extras 3 by Uhu (on 20. January 2018, 12:49) | 58 | 99 % |
| Optimization by djorr (on 23. June 2021, 16:10) | 19 | 97 % |
| Six-pack Linked Sudokus #8 by Genomico (on 15. September 2021, 04:10) | 40 | 99 % |
| Doppelt (Double Arrow) by tallcat (on 17. September 2021, 16:48) | 36 | 98 % |
| X-Sum Clues in the Grid by kolot (on 8. November 2021, 05:19) | 21 | 96 % |
| Multiplied Cages by RockyRoer (on 2. December 2021, 03:40) | 19 | 93 % |
| Uneasy Alliances by ViKingPrime (on 30. May 2024, 16:00) | 18 | 93 % |
| Night on the Galactic Railroad by sfushidahardy (on 19. August 2024, 00:04) | 22 | 96 % |
| Smallhat by the_cogito (on 21. April 2022, 17:27) | 53 | 95 % |
| Mercury Arrows (Thermo Arrow) by tallcat (on 23. May 2021, 23:22) | 30 | 93 % |
| Wall Sudoku by Phistomefel (on 22. December 2021, 23:59) | 93 | 99 % |
| Consecutive Sudoku by AstralSky (on 28. November 2022, 18:01) | 37 | 92 % |
| Lattice by pieguy (on 26. January 2023, 18:43) | 63 | 98 % |
| More by TotallyNormalCat (on 4. September 2021, 22:30) | 77 | 98 % |
| Min-Max-Sichtblöcke (4) by BFaw (on 14. December 2016, 10:00) | 20 | 94 % |
| Odd River - Prime Whispers Sudoku by ibn Muhyiddin (on 20. July 2020, 14:43) | 20 | 99 % |
| Gordian Knot by Joseph nehme (on 3. March 2021, 16:20) | 55 | 97 % |
