(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 | |
|---|---|---|---|
 | Small Phistomefel by Stoer (on 23. April 2023, 13:19) | 22 |  91 % |
| Thermos Construction by Prof.Dori (on 15. December 2023, 02:00) | 57 | 92 % |
| Chackstones (XVXV/Kropki pairs/X-sums) by dumediat (on 27. April 2024, 02:42) | 37 | 92 % |
| T-Time (Anti-Knight Renban Killer Sudoku) by Phistomefel (on 13. June 2023, 21:12) | 191 | 97 % |
| Glass Half Empty by mellowrobinson (on 12. August 2025, 16:19) | 35 | 96 % |
| Chaos Construction: Double Arrow by Xendari (on 14. November 2023, 02:19) | 81 | 96 % |
| 4-Stern-Star-Battle by CJK (on 1. July 2021, 10:09) | 50 | 94 % |
| Glass Half Summed (Chaos Construction) by sfushidahardy (on 25. August 2024, 01:10) | 68 | 98 % |
| Buchstabenpaarreihen (4) by BFaw (on 30. March 2016, 11:00) | 36 | 97 % |
| Scratches by PrimeWeasel (on 11. April 2021, 09:27) | 13 | 95 % |
| Mixed Doubles by Scruffamudda (on 4. November 2021, 23:37) | 13 | 98 % |
| Japanese Sums with Arrows by mathpesto (on 31. December 2021, 22:24) | 39 | 95 % |
| Black Eyes by Qodec (on 10. April 2022, 14:31) | 29 | 95 % |
| Mountain Aven by mormagli (on 2. October 2022, 04:37) | 15 | 90 % |
| Position Sums Fillomino #3: Internal Clues by ONeill (on 26. October 2022, 12:59) | 27 | 100 % |
| Friendly Indexers by thoughtbyte (on 1. June 2023, 06:18) | 12 | 91 % |
| Momohime's Human Beatbox Party by Morisenseiisgod (on 12. December 2023, 15:24) | 13 | 98 % |
| Ophidiophobia by marty_sears (on 14. August 2024, 14:45) | 151 | 97 % |
| Sandwiched Clues by RockyRoer (on 5. March 2021, 11:35) | 20 | 96 % |
| Regional Differences by apiyo (on 24. May 2021, 14:37) | 22 | 97 % |
