(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 | |
|---|---|---|---|
 | Castle Wall Fillomino by Agent (on 21. March 2023, 09:00) | 53 |  97 % |
| Parity Mirror by zegres (on 2. May 2022, 04:41) | 72 | 100 % |
| X-Count Mod 3 Sudoku by Timwi (on 2. May 2020, 05:21) | 18 | 90 % |
| Roller Coaster mit Extras 18 by Uhu (on 10. May 2020, 20:16) | 37 | 98 % |
| Galaxy Killer Key-Clone Sudoku by ahaupt (on 26. May 2020, 18:02) | 21 | 95 % |
| When X-Sums meet Killer by Joseph nehme (on 8. February 2021, 14:36) | 35 | 96 % |
| Parity Party XVI, "Block Party" by glum_hippo (on 4. March 2021, 05:54) | 18 | 95 % |
| Tartan by grkles (on 10. July 2021, 15:49) | 17 | 97 % |
| Forbidden Quads by SSG (on 21. October 2021, 07:12) | 23 | 90 % |
| Cliffs of Insanity by DarthParadox (on 27. June 2022, 00:06) | 18 | 92 % |
| Siphon (Region Sum Lines) by tallcat (on 11. August 2022, 08:00) | 116 | 99 % |
| X-Marks the Treasure Map by Maxentius (on 22. February 2023, 01:03) | 18 | 93 % |
| 27 Killer by Florian Wortmann (on 26. February 2023, 13:14) | 80 | 96 % |
| Saya's Skyscrapers by Morisenseiisgod (on 2. September 2023, 18:11) | 18 | 95 % |
| All the Same and Never 4 by Jrosas (on 17. May 2024, 19:14) | 17 | 92 % |
| Armada! Armada! by Black_Doom (on 25. May 2024, 15:15) | 17 | 90 % |
| Counting Castles by marty_sears (on 18. February 2024, 03:37) | 130 | 96 % |
| Duplicates Somedoku by blackjackfitz (on 2. March 2024, 20:42) | 134 | 98 % |
| Anti-Knight Killer Sudoku #3 by Phistomefel (on 11. February 2021, 23:20) | 107 | 95 % |
| Caduceus by PjotrV (on 2. June 2022, 13:11) | 52 | 100 % |
