(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 | |
|---|---|---|---|
 | Die Kryptos - S03E05: Spiral City Construction by tuace (on 30. October 2018, 10:14) | 49 |  98 % |
| The Disjointed Cube by Wecoc (on 8. January 2021, 01:57) | 56 | 96 % |
| Boundless (Many Variants!) by Aaronomys (on 31. May 2021, 11:28) | 15 | 96 % |
| Orderly Little Killer 3 by Strosahl (on 2. July 2021, 07:11) | 15 | 92 % |
| What's with the crust these days? by filuta (on 26. July 2021, 19:55) | 14 | 98 % |
| Pairs Party by Qodec (on 28. August 2021, 11:31) | 63 | 92 % |
| Alpes by lerroyy (on 26. February 2022, 20:52) | 18 | 92 % |
| Lion (Non-touching killer sudoku) by Qodec (on 18. May 2022, 11:58) | 106 | 94 % |
| Deflation by jwsinclair (on 13. December 2022, 20:42) | 39 | 94 % |
| Lithium + Neon by 99%Sneaky (on 14. June 2023, 19:58) | 14 | 98 % |
| Masyudoku by 3good5you (on 1. September 2023, 01:31) | 15 | 98 % |
| Edge Effects by arbitrary (on 9. March 2024, 03:50) | 18 | 94 % |
| 3 1 by 1 4 (on 13. March 2024, 00:31) | 20 | 92 % |
| Balance by Scojo (on 3. October 2024, 21:31) | 48 | 94 % |
| Cacophony by zetamath (on 5. August 2021, 18:19) | 87 | 96 % |
| Sudoku Variants Series (276) - Taxi Ride Sudoku by Richard (on 8. July 2020, 00:00) | 71 | 92 % |
| Roller Coaster Krypto by Uhu (on 11. November 2016, 13:47) | 52 | 98 % |
| Hidden Sums by jwsinclair (on 27. November 2021, 20:19) | 35 | 97 % |
| Quint Quads by Ned Howarth (on 29. June 2022, 09:55) | 43 | 93 % |
| Halligen by KNT (on 8. January 2023, 07:48) | 37 | 98 % |
