(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 | |
|---|---|---|---|
 | Split the Difference by Scojo (on 27. November 2025, 07:49) | 17 |  96 % |
| Congruity by Andrewsarchus (on 14. December 2025, 03:06) | 43 | 97 % |
| ✖ by Gliperal (on 27. June 2021, 08:20) | 93 | 99 % |
| Galactic Union (Killer / Spiral Galaxy / Chaos Construction) by Tacosian (on 23. December 2023, 23:26) | 98 | 99 % |
| Syzygy by jovi_al (on 13. March 2021, 18:05) | 89 | 98 % |
| Frak by zetamath (on 20. February 2022, 21:09) | 73 | 98 % |
| Shadow (Cave Skyscraper Hybrid) by tallcat (on 20. November 2022, 09:00) | 60 | 97 % |
| Hawaii (Spiral Galaxy Sudoku) by PjotrV (on 5. February 2022, 15:04) | 60 | 97 % |
| Third Degree by Die Hard (on 13. February 2024, 11:52) | 62 | 95 % |
| Pentopia Rundweg II by tuace (on 22. April 2019, 09:55) | 55 | 99 % |
| Parity Quads by NurglesGift (on 9. February 2025, 18:32) | 58 | 94 % |
| Japanische Höhle mit Irrwisch von den Außerirdischen by ibag (on 27. March 2018, 00:00) | 44 | 99 % |
| Chillicothe by glum_hippo (on 4. October 2023, 18:11) | 53 | 95 % |
| Chaos CaveSudoku by MagnusJosefsson (on 7. December 2022, 11:55) | 85 | 98 % |
| Enclosure by Xenonetix (on 21. September 2022, 01:11) | 42 | 100 % |
| Tachyons and Black Holes (Black Hole) by heliopolix (on 16. January 2023, 20:00) | 47 | 96 % |
| Overflow by IcyFruit (on 10. November 2023, 16:27) | 91 | 96 % |
| Zebediah Killgrave by starwarigami (on 24. November 2023, 10:01) | 77 | 95 % |
| Aim for the Sky by udukos (on 28. March 2021, 22:12) | 34 | 98 % |
| Supernova by Nahileon (on 3. November 2021, 20:32) | 76 | 99 % |
