(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 | |
|---|---|---|---|
 | Mayan Ruins (Run-on Renban) by riffclown (on 20. November 2023, 13:18) | 34 |  94 % |
| Cryptic Snakewords by marty_sears (on 26. January 2024, 02:34) | 43 | 98 % |
| Smoke and Mirrors by gdc (on 22. February 2024, 20:05) | 43 | 91 % |
| [Fog of War Series] 2.Interlinked by AstralSky (on 26. October 2022, 04:36) | 71 | 91 % |
| Killer Kropki Sudoku by Willy Wonka (on 6. September 2020, 17:16) | 50 | 96 % |
| Irregular Antiking Sudoku by spxtr (on 15. September 2020, 01:45) | 24 | 96 % |
| Adamas by Polycarp (on 21. March 2021, 02:30) | 25 | 92 % |
| Kropki Sums by mathpesto (on 19. December 2021, 16:26) | 25 | 95 % |
| The River by wooferzfg (on 20. March 2022, 06:24) | 44 | 96 % |
| Pentomino Yajilin by KNT (on 31. May 2024, 20:24) | 96 | 99 % |
| Tatlins Turm (Chaos Construction) by glum_hippo (on 22. January 2024, 22:52) | 57 | 95 % |
| U-Bahn with Empty Cells by Niverio (on 28. June 2024, 21:23) | 38 | 99 % |
| Hybrid Series #1: Pentominous Mid-Loop by Tyrgannus (on 11. January 2025, 11:32) | 33 | 98 % |
| Ish-doku by ChinStrap (on 24. October 2025, 17:48) | 36 | 96 % |
| Vampires by grkles (on 22. October 2021, 02:12) | 43 | 98 % |
| Acropora (Chaos Construction) by Agent (on 13. June 2023, 09:00) | 91 | 98 % |
| The Ultimate Prime Cages by Xenonetix (on 11. June 2024, 23:45) | 100 | 98 % |
| Post von den Außerirdischen by ibag (on 6. September 2014, 06:09) | 33 | 97 % |
| Japanisches Summen-Masyu by Uhu (on 20. June 2017, 17:56) | 48 | 99 % |
| Gaelic Knot by cam (on 27. September 2020, 20:08) | 14 | 93 % |
