(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 | |
|---|---|---|---|
 | Cyclone (Secret Satan 4-in-1 Sudoku/Shading/Loop Hybrid) by MaizeGator (on 5. January 2025, 03:30) | 22 |  97 % |
| wanna double dutch? by aqjhs (on 15. September 2025, 21:21) | 21 | 100 % |
| Doubler Twin Deconstruction by Christounet (on 29. January 2025, 18:19) | 36 | 99 % |
| Heart Breaker (Arrow Sudoku) by FryTheGuy (on 27. May 2021, 03:36) | 19 | 94 % |
| The inconvenient square root (chaos construction) by filuta (on 19. December 2021, 13:30) | 38 | 99 % |
| Riverbank - Episode 4: Nessie by henrypijames (on 20. May 2022, 09:26) | 18 | 98 % |
| Tiger's Jaw by Samish (on 8. August 2022, 19:23) | 19 | 94 % |
| Jet Lag (Dynamic Fog of War, Chaos Construction) by DubiousMobius (on 6. December 2024, 04:21) | 20 | 97 % |
| Belagerungsturm by Myxo (on 22. September 2024, 14:12) | 39 | 98 % |
| Nuriquarium Sudoku by Jay Dyer (on 26. January 2023, 12:46) | 55 | 93 % |
| Wichtel 2020 (4): Memo an den Weihnachtsmann by wichtel (on 27. April 2021, 02:02) | 16 | 98 % |
| Crypto Lying Japanese Cavescraper Ring for polar by KNT (on 20. December 2022, 02:44) | 37 | 99 % |
| Sailing by ThePedallingPianist (on 15. February 2023, 00:18) | 22 | 98 % |
| Zodiac Project: Leo by ChinStrap (on 16. July 2025, 13:54) | 37 | 94 % |
| The S-Cell Miracle by Niverio (on 22. May 2022, 16:40) | 56 | 97 % |
| Unique Japanese Sum Sudoku by tesseralis (on 28. July 2023, 05:34) | 82 | 97 % |
| Roller Coaster Yin Yang Cipher by Piatato (on 26. December 2022, 11:26) | 32 | 100 % |
| Chaos In Frankfurt! (Secret Satan 2023) by Niverio (on 1. January 2024, 17:25) | 38 | 100 % |
| Runway (Killer sudoku with maximum totals + arrows) by Qodec (on 6. October 2024, 19:06) | 81 | 95 % |
| Schrödinger's Deconstruction by mathpesto (on 19. June 2022, 13:57) | 53 | 98 % |
