(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 | |
|---|---|---|---|
 | Killer Sudoku #2 — 'ZooZ' by PixelPlucker (on 31. October 2021, 13:55) | 41 |  91 % |
| Learn the Alphabet: B is for Between Line by Crusader175 (on 26. January 2022, 17:30) | 31 | 94 % |
| Integral Magic Squares by mathpesto (on 16. April 2022, 18:32) | 16 | 93 % |
| Guillotine by Qodec (on 4. September 2022, 12:20) | 49 | 94 % |
| Room Service by Xenonetix (on 9. October 2022, 02:02) | 26 | 93 % |
| Companions by Joseph nehme (on 3. November 2022, 09:46) | 17 | 91 % |
| HBD Niverio by twototenth (on 27. December 2022, 08:00) | 74 | 96 % |
| Doublomania by lepton (on 3. January 2023, 21:14) | 26 | 98 % |
| Thursday by Listopad (on 9. February 2023, 08:16) | 20 | 90 % |
| Misdirection by MicroStudy (on 24. May 2023, 15:31) | 41 | 95 % |
| Snails by Twan2797 (on 23. August 2023, 16:35) | 38 | 94 % |
| Masyudoku [Region Sum Line, Masyu] by 3good5you (on 1. September 2023, 01:31) | 17 | 98 % |
| Gossip by Myxo (on 1. October 2023, 10:46) | 27 | 90 % |
| Happy Birthday to Naomi by Fool on Hill (on 31. March 2024, 13:51) | 26 | 95 % |
| Galaxies Collide by Prof.Dori (on 3. April 2024, 15:31) | 79 | 98 % |
| Seilkunde by Blashyrkh (on 16. May 2024, 17:40) | 36 | 95 % |
| Crossbow (Arrow variant sudoku) by Qodec (on 10. July 2024, 15:34) | 71 | 94 % |
| RAT RUN 19: Brainwaves by marty_sears (on 18. December 2024, 01:00) | 397 | 96 % |
| Glass Numbered Rooms by Xenonetix (on 27. April 2022, 01:23) | 72 | 99 % |
| The Clues, the Whole Clues, and Nothing but the Clues. by Abdul the Killer (on 23. July 2024, 12:34) | 62 | 97 % |
