(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 | |
|---|---|---|---|
 | Confluence by mathpesto (on 24. April 2023, 17:00) | 65 |  98 % |
| Schrödinger Sudkuro by ICHTUES (on 30. October 2022, 06:00) | 49 | 98 % |
| Sun Chariot by Miky (on 14. April 2021, 00:17) | 45 | 94 % |
| Aqres of Shikaku Country (9x9) by mathpesto (on 29. October 2022, 22:57) | 35 | 98 % |
| Monster Math by ThePedallingPianist (on 26. October 2023, 02:40) | 35 | 100 % |
| Round Robin by IcyFruit (on 12. January 2024, 21:24) | 37 | 97 % |
| Dedicated to wisty by Myxo (on 21. January 2025, 14:25) | 35 | 93 % |
| Thermo Sudoku by trivial171 (on 6. September 2020, 19:48) | 61 | 97 % |
| Zweiter Pfeilchenstrauß by glum_hippo (on 24. August 2020, 17:26) | 25 | 93 % |
| Compass Fillomino #3: Large grid by MagnusJosefsson (on 23. April 2021, 17:44) | 47 | 97 % |
| Imbalanced Flower by MavericksJD (on 19. June 2022, 21:33) | 31 | 92 % |
| The Fifteenth Day of Christmas by cristophermoore (on 18. December 2022, 07:01) | 50 | 98 % |
| Sandwich X Circles by ICHTUES (on 8. October 2023, 06:00) | 22 | 91 % |
| did you say walkies!? by aqjhs (on 27. June 2025, 09:27) | 25 | 99 % |
| Overflow by IcyFruit (on 10. November 2023, 16:27) | 95 | 95 % |
| 2d Wave Particles by zetamath (on 15. July 2021, 18:22) | 32 | 95 % |
| Mean World Syndrome [Mean Arrow, Kropki] by Miky (on 1. May 2023, 17:29) | 36 | 96 % |
| Wichtel 2015 (6): MERRY CHRISTMAS! by wichtel (on 18. May 2016, 20:15) | 41 | 99 % |
| A Wonderful Discovery - Dedicated to Gliperal by damasosos92 (on 21. May 2023, 02:14) | 46 | 97 % |
| Motel (Deconstruction: Numbered Rooms) by purpl (on 8. April 2022, 16:42) | 50 | 98 % |
