(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 | |
|---|---|---|---|
 | Little Killer Sudoku #3 by Phistomefel (on 12. September 2020, 11:05) | 62 |  93 % |
| Boundless (Many Variants!) by Aaronomys (on 31. May 2021, 11:28) | 16 | 96 % |
| Pairs Party by Qodec (on 28. August 2021, 11:31) | 63 | 92 % |
| Good Luck, Bad Luck by oberon (on 21. February 2022, 20:29) | 37 | 97 % |
| Alpes by lerroyy (on 26. February 2022, 20:52) | 18 | 92 % |
| Counterpoint (Renban Arrow) by tallcat (on 16. July 2022, 08:30) | 86 | 98 % |
| Lithium + Neon by 99%Sneaky (on 14. June 2023, 19:58) | 14 | 98 % |
| Unzipped by marty_sears (on 30. October 2023, 00:41) | 32 | 95 % |
| Edge Effects by arbitrary (on 9. March 2024, 03:50) | 18 | 94 % |
| five pointed stars, five lettered cells (Pentominous/Star Battle) by Nell Gwyn (on 18. February 2025, 20:18) | 15 | 100 % |
| Domino Fever (Entropy Edition) by Mad-Tyas (on 21. February 2022, 23:32) | 72 | 94 % |
| Even X-Sums by Realshaggy (on 24. December 2021, 05:00) | 47 | 97 % |
| Balance by Scojo (on 3. October 2024, 21:31) | 56 | 95 % |
| Vibrations (Killer, Thermo) by Niverio (on 30. September 2023, 17:01) | 129 | 95 % |
| The Big Zipper by marty_sears (on 1. November 2023, 14:04) | 124 | 95 % |
| Supermoon by ViKingPrime (on 19. October 2024, 21:45) | 39 | 95 % |
| Project 37 by Blashyrkh (on 6. December 2023, 13:48) | 71 | 93 % |
| Scientific Method (Killer) by tallcat (on 5. March 2022, 04:46) | 86 | 97 % |
| Circles and Thermos by stimim (on 9. September 2023, 19:28) | 115 | 96 % |
| Doppel-Killer Sudoku 0/1-9 by julius64 (on 27. January 2011, 22:21) | 46 | 94 % |
