(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 | |
|---|---|---|---|
 | S.S. Elroy [Thermo Palindrome Sudoku] by Gene The Supreme (on 28. March 2026, 19:34) | 20 |  91 % |
| Chaos Construction: Numbered Regions #1 by Jesper (on 24. September 2022, 15:15) | 171 | 100 % |
| Killer Shikoku by the_cogito (on 9. March 2022, 00:16) | 62 | 96 % |
| Colorimetry (Four Color Pentomino Sums) by Agent (on 19. August 2025, 09:00) | 58 | 97 % |
| Cryptic Skyscrapers (Alphabet Soup) by emmettcito (on 21. March 2021, 00:30) | 38 | 98 % |
| arROw SudOkU rEduX by filuta (on 20. April 2021, 13:49) | 18 | 93 % |
| Y Are We Whispering? by glum_hippo (on 18. September 2021, 04:12) | 36 | 94 % |
| Stepwell by mormagli (on 14. May 2022, 07:17) | 20 | 93 % |
| Sum Kind of Maze by mormagli (on 28. July 2022, 19:24) | 18 | 92 % |
| A Blind Killer by bodemeister (on 17. January 2023, 08:29) | 18 | 97 % |
| Silent Suguru by dennischen (on 27. April 2023, 01:12) | 55 | 99 % |
| Hybrid Star Battle Series (017) - Easy as ABC by BenceJoful (on 6. May 2023, 01:45) | 18 | 97 % |
| Is 4 a Low Digit? by blackjackfitz (on 30. August 2023, 03:23) | 24 | 92 % |
| Deconstruction of Whisper Tree (11x11) by SparkNights (on 4. February 2024, 07:05) | 40 | 97 % |
| Yin-Yang-Yong by marty_sears (on 13. May 2024, 00:27) | 100 | 97 % |
| Dust Torus (Black Hole) by heliopolix (on 14. September 2024, 00:00) | 24 | 98 % |
| Canyonlands (A38 + Rassi Silai) by sfushidahardy (on 16. March 2025, 17:07) | 17 | 93 % |
| Directed Entropy by egubachu (on 11. June 2025, 22:11) | 20 | 91 % |
| HeX-Sums by qoala (on 13. June 2025, 09:00) | 19 | 90 % |
| Twin Chaos Constructions: X-sums in Two Ways (2x8x8) by Playmaker6174 (on 25. April 2026, 13:00) | 17 | 98 % |
