(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 | |
|---|---|---|---|
 | Position Sums mit Renban-Streifen by glum_hippo (on 29. June 2021, 07:23) | 29 |  99 % |
| Liar Japanese Sums #3: Renban Square by Niverio (on 8. January 2023, 21:45) | 61 | 98 % |
| Anti Minesweeper Chaos by Polycarp (on 29. April 2023, 20:24) | 30 | 93 % |
| Yozzy by zetamath (on 6. May 2024, 02:28) | 34 | 95 % |
| Bodysnatchers by AnalyticalNinja (on 1. October 2024, 20:07) | 112 | 99 % |
| Seesaw (Killer Only Sudoku) by Celery (on 10. December 2023, 22:34) | 50 | 97 % |
| Killer Windrad by tuace (on 30. July 2016, 14:45) | 44 | 98 % |
| Cursed Quiver (Arrow Deconstruction) by Xendari (on 6. October 2022, 09:10) | 49 | 99 % |
| Temperature (Thermo, Entropy) by Mad-Tyas (on 30. January 2023, 08:22) | 51 | 94 % |
| Chaos Construction: X-Sums / Sandwich by KNT (on 13. April 2022, 17:12) | 58 | 98 % |
| Millstone by jwsinclair (on 13. June 2024, 20:59) | 71 | 97 % |
| Perfectly Balanced by IcyFruit (on 13. February 2025, 14:33) | 69 | 96 % |
| Chaotic Equality by Knickolas (on 8. December 2022, 21:07) | 77 | 98 % |
| X-Ray Vision (Yin Yang X-Sums Sudoku) by Agent (on 6. September 2022, 09:00) | 70 | 98 % |
| Ma'at's Transcript: Order from Chaos (Chaos Construction) by Chilly (on 13. July 2022, 13:07) | 83 | 100 % |
| Half Life (Yin Yang Deconstruction) by Agent (on 30. August 2022, 09:00) | 78 | 99 % |
| Sky-Skyscraper by Phistomefel (on 22. March 2024, 15:29) | 81 | 99 % |
| Zoom Out by Myxo (on 30. July 2024, 12:22) | 105 | 99 % |
| 5-ABCtje by Richard (on 28. August 2009, 09:01) | 65 | 90 % |
| Der verlorene Schlüssel by berni (on 5. March 2010, 14:34) | 51 | 98 % |
