(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 | |
|---|---|---|---|
 | Confined Sandwich Chaos by PrimeWeasel (on 6. July 2022, 16:55) | 55 |  97 % |
| Never (Yajilin/Sudoku) by Wessel Strijkstra (on 6. November 2022, 17:41) | 51 | 95 % |
| Cave Express (Japanese Sums Cipher) by Agent (on 21. February 2023, 09:00) | 52 | 99 % |
| Fillomino Sudoku by spxtr (on 29. August 2020, 08:26) | 30 | 95 % |
| Remanence by Emphyrio (on 12. October 2021, 04:24) | 35 | 97 % |
| Chaos Construction: Numbered Regions #2 by Jesper (on 2. October 2022, 15:14) | 91 | 100 % |
| Killer Kropki Cages sequel by Ryx (on 28. March 2023, 06:45) | 33 | 91 % |
| Slythering [Liar Japanese Sums Snake] by Christounet (on 4. June 2024, 07:54) | 30 | 100 % |
| 10-in-9 Isolation Sudoku by Phistomefel (on 5. April 2020, 12:07) | 44 | 97 % |
| Sirius by jovi_al (on 19. February 2022, 03:07) | 40 | 98 % |
| Vignettes by zetamath (on 18. July 2022, 00:54) | 83 | 99 % |
| Stairity - Chaos Construction by the_cogito (on 10. August 2022, 03:07) | 87 | 98 % |
| Safe Distances by Emphyrio (on 26. September 2022, 16:54) | 46 | 93 % |
| Toutatis by IcyFruit (on 9. May 2024, 14:35) | 42 | 93 % |
| Prime-Co Sweepers by XeonRisq (on 11. January 2023, 17:00) | 47 | 100 % |
| Pack of Aces by mormagli (on 8. February 2024, 02:20) | 52 | 96 % |
| Heqtare by mathpesto (on 2. September 2022, 18:31) | 56 | 99 % |
| Teenage Dream by starwarigami (on 6. September 2022, 07:37) | 57 | 97 % |
| Ancient Ruins (Fog, BYO Killer, Nurikabe) by lepton (on 6. February 2023, 16:24) | 65 | 95 % |
| Some Kind of Chaos by marty_sears (on 24. May 2024, 09:25) | 125 | 98 % |
