(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 | |
|---|---|---|---|
 | Ambiguity 2 by zetamath (on 13. April 2021, 02:44) | 46 |  94 % |
| Wichtel 2020 (6): Rundweg "Fünf Jahreszeiten" by wichtel (on 27. May 2021, 20:02) | 39 | 99 % |
| All Crossed Up by Polycarp (on 13. May 2021, 04:45) | 26 | 95 % |
| The Fairest in the Land (Inequality Series #6) by twototenth (on 19. October 2021, 08:00) | 19 | 91 % |
| Four Lockout Lines by Lizzy01 (on 30. October 2021, 17:19) | 35 | 98 % |
| Killer Sudoku #2 ('ZooZ') by PixelPlucker (on 31. October 2021, 13:55) | 44 | 91 % |
| Marupeke Sudoku by Crusader175 (on 7. November 2021, 08:08) | 26 | 92 % |
| Integral Magic Squares by mathpesto (on 16. April 2022, 18:32) | 18 | 93 % |
| Constellation by tenaliraman (on 15. July 2022, 09:03) | 46 | 96 % |
| Entropy Production by starwarigami (on 30. November 2022, 09:15) | 26 | 96 % |
| HBD Niverio by twototenth (on 27. December 2022, 08:00) | 76 | 96 % |
| Snakomino [Level #1] by Christounet (on 1. February 2023, 22:17) | 62 | 100 % |
| Japanese Sums #1: Vanilla by Myxo (on 19. April 2023, 16:00) | 96 | 98 % |
| Long Island [Shimaguni Fillomino] by MicroStudy (on 5. May 2023, 01:11) | 57 | 97 % |
| Partition [Little Killer, Yin-Yang Sight Arrows] by 3good5you (on 27. July 2023, 08:56) | 17 | 95 % |
| Snails by Twan2797 (on 23. August 2023, 16:35) | 38 | 94 % |
| XY-Differences Fillomino 2 by glum_hippo (on 30. August 2023, 19:51) | 38 | 92 % |
| Masyudoku [Region Sum Line, Masyu] by 3good5you (on 1. September 2023, 01:31) | 18 | 98 % |
| Companies (Skyscraper, Product Ltd) by Crusader175 (on 5. December 2023, 14:00) | 28 | 94 % |
| German Summing Doppelganger by feethy (on 3. March 2024, 18:40) | 15 | 100 % |
