(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 | |
|---|---|---|---|
 | 真笑Puzzles023--N-Sums Sudoku--Counter by cdwg2000 (on 5. February 2021, 17:45) | 30 |  100 % |
| Palindromaze by FinnishGuy (on 14. September 2021, 20:25) | 31 | 90 % |
| Remanence by Emphyrio (on 12. October 2021, 04:24) | 36 | 97 % |
| Schrödinger's Arrows by starwarigami (on 14. January 2022, 04:34) | 31 | 96 % |
| Killer Kropki Cages sequel by Ryx (on 28. March 2023, 06:45) | 33 | 91 % |
| Typhon by Kafkapharnaum (on 24. August 2024, 19:41) | 37 | 98 % |
| Mictēcacihuātl (Castle Wall Delta + Directed U-Bahn) by sfushidahardy (on 22. May 2025, 08:11) | 29 | 95 % |
| WPC 2016 Training - Pentominos by uvo (on 12. July 2017, 15:33) | 40 | 98 % |
| 10-in-9 Isolation Sudoku by Phistomefel (on 5. April 2020, 12:07) | 46 | 97 % |
| Stairity - Chaos Construction by the_cogito (on 10. August 2022, 03:07) | 91 | 98 % |
| Safe Distances by Emphyrio (on 26. September 2022, 16:54) | 46 | 93 % |
| Meidjuluk Fillomino Permaculture by Agent (on 27. June 2023, 09:00) | 89 | 97 % |
| Displacement (Arrow Sudoku) by Phistomefel (on 10. May 2022, 19:07) | 103 | 98 % |
| Pack of Aces by mormagli (on 8. February 2024, 02:20) | 52 | 96 % |
| Heqtare by mathpesto (on 2. September 2022, 18:31) | 61 | 99 % |
| Teenage Dream by starwarigami (on 6. September 2022, 07:37) | 57 | 97 % |
| Venn Diagram Loops by Prof.Dori (on 9. May 2024, 16:44) | 53 | 99 % |
| Cryptic Coin (Arrow Kropki Sudoku) (ft. Tyrgannus) by Agent (on 9. September 2022, 09:00) | 72 | 98 % |
| Nostalgia (Build your own Arrow) by Sartor (on 3. August 2025, 18:29) | 64 | 97 % |
| The Usual Suspects by zetamath (on 22. October 2021, 02:39) | 78 | 98 % |
