(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 | |
|---|---|---|---|
 | Fillomino Aquarium by Phistomefel (on 16. January 2022, 00:44) | 85 |  100 % |
| Chaos Construction: Killer Cages by KNT (on 4. April 2022, 23:31) | 116 | 98 % |
| Roller Coaster mit Extras 13 by Uhu (on 21. March 2019, 22:34) | 44 | 99 % |
| A Powerful Duo (Entropy, Anti-Knight) by Mad-Tyas (on 16. May 2023, 09:08) | 44 | 94 % |
| Knight's Whirlpool by SudokuExplorer (on 10. February 2022, 00:30) | 98 | 98 % |
| Killer Sudoku - Twirl by Phistomefel (on 6. December 2020, 11:18) | 62 | 97 % |
| Evil Eyes 4 v. 4 by Luigi (on 17. June 2010, 14:45) | 19 | 97 % |
| Puffer Fish by Qodec (on 28. November 2020, 22:05) | 43 | 98 % |
| Information Paradox (Advanced Black Hole) by heliopolix (on 6. May 2023, 01:38) | 17 | 100 % |
| Friendly Indexing Miracle by thoughtbyte (on 5. June 2023, 18:29) | 38 | 95 % |
| Stronghold by fjam (on 31. May 2024, 19:04) | 17 | 93 % |
| Two Truths and a Lie by zetamath (on 20. September 2021, 14:48) | 137 | 98 % |
| Building between by Paletron (on 10. August 2023, 20:20) | 52 | 95 % |
| Self-determination by stephane.bura (on 5. September 2022, 15:46) | 72 | 97 % |
| Caged Knights Versus The Archers by Jeet Sampat (on 16. May 2023, 18:33) | 38 | 96 % |
| A Wonderful Discovery - Dedicated to Gliperal by damasosos92 (on 21. May 2023, 02:14) | 40 | 97 % |
| Los Angeles by ICHTUES (on 24. July 2022, 06:00) | 61 | 98 % |
| Confluence by mathpesto (on 24. April 2023, 17:00) | 62 | 98 % |
| Mount Elbrus (Killer sudoku with doublers) by Qodec (on 4. February 2024, 17:22) | 116 | 98 % |
| Thonk? by purpl (on 3. May 2022, 00:26) | 25 | 94 % |
