(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 | |
|---|---|---|---|
 | Negatively Constrained Exploded Compass Sudoku by stephane.bura (on 8. March 2021, 09:00) | 19 |  94 % |
| Heterochromia (Killer Sudoku) by emmettcito (on 30. March 2021, 00:42) | 55 | 96 % |
| Little Killer by Strosahl (on 7. April 2021, 05:36) | 33 | 99 % |
| California skyscraper sudoku by Shinya (on 12. May 2021, 09:02) | 17 | 94 % |
| Palindrome Builder by Quarterthru (on 10. July 2021, 17:00) | 17 | 95 % |
| Triple Decker by Mimaamakim (on 29. August 2021, 20:28) | 35 | 98 % |
| Equal Sudoku by kolot (on 25. October 2021, 07:39) | 26 | 99 % |
| Anti-Knight, Arrows, and Renban by Jeet Sampat (on 26. October 2021, 23:26) | 39 | 94 % |
| Secrets and Lines by starwarigami (on 2. November 2021, 19:23) | 77 | 96 % |
| Killer Ambiguity by abed hawila (on 8. February 2022, 00:34) | 45 | 97 % |
| Repeater by mathpesto (on 19. March 2022, 04:47) | 53 | 99 % |
| Progressive Divisors by DiMono (on 3. April 2022, 21:10) | 49 | 96 % |
| Ghost by Jay Dyer (on 13. April 2022, 15:50) | 27 | 97 % |
| Build Your Own Killer: High Pressure by Playmaker6174 (on 14. September 2022, 22:27) | 44 | 100 % |
| The Devil's Cage by TinkerTroy (on 3. October 2022, 18:36) | 39 | 96 % |
| Cursed Quiver (Arrow Deconstruction) by Xendari (on 6. October 2022, 09:10) | 50 | 99 % |
| Squbler's 100 by mormagli (on 18. October 2022, 02:39) | 38 | 95 % |
| Points 'round by damasosos92 (on 18. April 2023, 20:01) | 17 | 91 % |
| Anti Minesweeper Chaos by Polycarp (on 29. April 2023, 20:24) | 32 | 93 % |
| E ∩ tropy (Killer, Entropy Theme) by Crusader175 (on 20. May 2023, 16:00) | 35 | 95 % |
