(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 | |
|---|---|---|---|
 | A Quiver of Snakes by The Book Wyrm (on 18. June 2023, 10:07) | 27 |  92 % |
| Downtown Fog by apiyo (on 21. June 2023, 13:52) | 63 | 90 % |
| Schrödinger 303: S-Duality by ViKingPrime (on 9. September 2024, 17:30) | 26 | 91 % |
| TRICKY - Buchstabenrätsel / Letter Puzzle by DocLogic (on 16. April 2024, 15:44) | 30 | 97 % |
| Northwest Wind by SXH (on 22. December 2024, 07:06) | 35 | 91 % |
| Yin Yang Kropki Sudoku by Phistomefel (on 19. April 2022, 10:24) | 102 | 98 % |
| Bullseye Sudoku by RockyRoer (on 29. July 2020, 21:59) | 49 | 97 % |
| Read Between the Lines (Build Your Own Puzzle) by tallcat (on 8. December 2021, 03:56) | 88 | 99 % |
| Two Twos and a Nine by ChinStrap (on 22. January 2025, 20:50) | 42 | 93 % |
| Don't Know What We Dig 'em For by twototenth (on 9. November 2021, 08:00) | 46 | 100 % |
| Killer Sudoku - The Knot by Phistomefel (on 31. August 2020, 23:10) | 90 | 99 % |
| Lügner Rundwege - Liar Loops by Calavera (on 17. November 2009, 19:32) | 62 | 97 % |
| Japanische Summen mit 50 by ibag (on 7. September 2018, 08:50) | 59 | 98 % |
| Cyclic Thermo Sudoku by trivial171 (on 29. April 2020, 03:43) | 14 | 93 % |
| Tangled Arrows (Arrow sudoku) by Aspartagcus (on 23. October 2020, 23:32) | 15 | 95 % |
| arROw SudOkU by filuta (on 1. March 2021, 18:08) | 24 | 90 % |
| Adorable Fury by DiMono (on 5. October 2021, 17:30) | 19 | 94 % |
| The Toppling Tree by fjam (on 9. January 2022, 19:29) | 25 | 99 % |
| Swords by antiknight (on 5. April 2022, 20:45) | 40 | 93 % |
| Think outside the snake by filuta (on 25. June 2022, 21:13) | 42 | 96 % |
