(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 | |
|---|---|---|---|
 | Different, But Still Wrogn by DiMono (on 3. June 2022, 23:39) | 77 |  97 % |
| Propellers by fritzdis (on 6. March 2021, 15:35) | 49 | 98 % |
| Arrow Sudoku by PotatoHead21 (on 26. April 2021, 09:02) | 23 | 98 % |
| Ta(x)i-Cab Sums: by RockyRoer (on 6. December 2020, 13:35) | 26 | 91 % |
| Anti-Knight, Arrows, and Renban by Jeet Sampat (on 26. October 2021, 23:26) | 31 | 95 % |
| Schrödinger's Arrows by starwarigami (on 14. January 2022, 04:34) | 27 | 95 % |
| Repeater by mathpesto (on 19. March 2022, 04:47) | 51 | 99 % |
| 8-Color Theorem by the_cogito (on 14. June 2022, 19:10) | 27 | 97 % |
| Implications of Parity by Niverio (on 30. July 2022, 13:06) | 53 | 98 % |
| The "Sum of Sums" Puzzle (that no one asked for) by Jeet Sampat (on 24. January 2023, 17:35) | 28 | 99 % |
| Red Lodge, Montana (Sudoku-Creek Hybrid) by mathpesto (on 24. December 2023, 17:10) | 110 | 98 % |
| kNights, uNite! by Alphish (on 17. July 2020, 02:33) | 33 | 91 % |
| SC24 - Region Sum Lines 2 by kuraban (on 22. November 2022, 19:33) | 30 | 92 % |
| The Big One by IcyFruit (on 25. January 2024, 14:04) | 37 | 95 % |
| Killers and Palindromes by tenaliraman (on 3. January 2021, 06:45) | 35 | 98 % |
| 159 Sandwiches by RockyRoer (on 19. February 2021, 21:33) | 32 | 99 % |
| Rigel (Arrow Sudoku) by emmettcito (on 27. April 2021, 17:01) | 37 | 98 % |
| Ballast by wooferzfg (on 29. July 2023, 23:07) | 29 | 100 % |
| Vacancy (Chaos Construction) by thoughtbyte (on 28. August 2023, 06:30) | 70 | 96 % |
| Fourteen Arrows by FryTheGuy (on 14. September 2021, 06:47) | 38 | 95 % |
