(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 | |
|---|---|---|---|
 | Quadrarrows by Jay Dyer (on 11. May 2024, 23:02) | 89 |  98 % |
| quadcopter by arctan (on 28. January 2026, 09:50) | 103 | 91 % |
| From pillar to post - (Killer, Diagonal sudoku) by Mr.Menace (on 30. November 2023, 19:48) | 96 | 95 % |
| 1K Sums by mathpesto (on 20. April 2022, 02:41) | 78 | 99 % |
| All But One by Scruffamudda (on 16. August 2023, 15:20) | 83 | 94 % |
| Topsy-Turvy by zetamath (on 1. August 2022, 19:41) | 82 | 95 % |
| Little Killer X Sudoku by Phistomefel (on 25. April 2020, 08:15) | 86 | 94 % |
| Double Chillomino by mathpesto (on 18. April 2024, 01:31) | 74 | 100 % |
| Tilt-a-Whirl by zetamath (on 17. October 2023, 17:38) | 77 | 93 % |
| Slitherlink Cave Sudoku by RockyRoer (on 16. August 2023, 14:05) | 68 | 97 % |
| Stickiest Notes by jwsinclair (on 24. January 2026, 22:00) | 147 | 97 % |
| Switchy by ICHTUES (on 11. December 2022, 06:00) | 69 | 95 % |
| That’s Even Better (Little Killer, Kropki Sudoku) by Mr.Menace (on 5. November 2024, 18:34) | 78 | 96 % |
| Battle With The Archers 24: Knight's Testimony by Playmaker6174 (on 10. December 2021, 10:29) | 63 | 93 % |
| Chaos Construction: Split Killers by XeonRisq (on 14. August 2022, 05:00) | 70 | 95 % |
| Meanest Mini by chameleon (on 1. January 2024, 17:10) | 74 | 98 % |
| Sudoku Variants Series (326) - Odd-Even Sandwich Sudoku by Richard (on 23. June 2021, 00:00) | 62 | 94 % |
| Entropy RSL by Mad-Tyas (on 2. May 2023, 09:02) | 65 | 97 % |
| Zodiac Project: Suguru's Surge by gdc (on 27. June 2024, 15:42) | 131 | 97 % |
| Halligen II by tuace (on 9. February 2014, 13:00) | 56 | 95 % |
