(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 | |
|---|---|---|---|
 | Between Knights and Arrows by Phistomefel (on 21. February 2021, 12:22) | 122 |  95 % |
| Chaos Construction - Border Relations by Niverio (on 3. May 2024, 12:35) | 97 | 98 % |
| The Facehugger by sonicbyte (on 12. December 2020, 23:30) | 35 | 96 % |
| The Four Pyramids by EricRathbun (on 10. December 2022, 23:03) | 56 | 96 % |
| Cave of Loops by Myxo (on 7. December 2022, 11:52) | 62 | 99 % |
| Odd/Even Killer Sudoku (#4) - No given cage totals by Mr.Menace (on 30. November 2020, 22:25) | 17 | 96 % |
| Arrow Sudoku by abed hawila (on 17. February 2021, 21:51) | 74 | 97 % |
| 100 Streams of Zetatude (renban, region sum, doublers) by Chilly (on 18. October 2022, 18:23) | 16 | 94 % |
| Sudokabe [Nurikabe Deconstruction] by Christounet (on 20. March 2024, 12:08) | 45 | 99 % |
| Eternal Recurrence by Kafkapharnaum (on 11. October 2025, 23:11) | 19 | 94 % |
| Top Floor by ThePedallingPianist (on 7. January 2026, 01:20) | 19 | 92 % |
| Warp Speed Factor 4 by The Bard (on 5. January 2026, 02:55) | 51 | 96 % |
| pin7guin loves ABCtjes too by ibag (on 6. September 2017, 00:00) | 24 | 92 % |
| Spurious Skyscrapers by Yawnus (on 12. March 2023, 13:54) | 27 | 91 % |
| The Serpent Devouring Rome by JeffWajes (on 18. March 2024, 01:16) | 28 | 91 % |
| Japanese Sums #5: Disposition by Myxo (on 10. October 2023, 11:55) | 67 | 98 % |
| الشمس والقمر (ashshams walqamar) by mathpesto (on 31. March 2025, 07:17) | 41 | 99 % |
| F-Puzzle by PulverizingPancake (on 16. April 2021, 03:40) | 42 | 93 % |
| Portal Sum - Little Killer Sudoku by Playmaker6174 (on 22. April 2022, 16:46) | 22 | 96 % |
| Nestification Jigsaw 2 by Lyun Licuss (on 29. August 2024, 19:51) | 12 | 93 % |
