(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 | |
|---|---|---|---|
 | What are the odds? (Parity killer/little killer) by sujoyku (on 18. August 2023, 10:15) | 39 |  93 % |
| Läufer Loop by Prof.Dori (on 23. September 2024, 12:17) | 37 | 99 % |
| 27 Killer by Florian Wortmann (on 26. February 2023, 13:14) | 83 | 96 % |
| Anti-Knight Killer Sudoku #3 by Phistomefel (on 11. February 2021, 23:20) | 111 | 96 % |
| Duplicates Somedoku by blackjackfitz (on 2. March 2024, 20:42) | 139 | 98 % |
| X-Count Mod 3 Sudoku by Timwi (on 2. May 2020, 05:21) | 18 | 90 % |
| 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 % |
| Reservation for Eight by apiyo (on 25. March 2021, 09:16) | 20 | 97 % |
| Tellurium Chaos by Nityant5 (on 12. May 2021, 13:02) | 72 | 100 % |
| Tartan by grkles (on 10. July 2021, 15:49) | 17 | 97 % |
| Forbidden Quads by SSG (on 21. October 2021, 07:12) | 25 | 90 % |
| Shikasudoku by Qodec (on 8. November 2021, 18:44) | 36 | 94 % |
| Caduceus by PjotrV (on 2. June 2022, 13:11) | 54 | 100 % |
| X-Marks the Treasure Map by Maxentius (on 22. February 2023, 01:03) | 19 | 93 % |
| Route 5 (Instructionless) by Agent (on 16. January 2024, 09:00) | 37 | 100 % |
| Armada! Armada! by Black_Doom (on 25. May 2024, 15:15) | 17 | 90 % |
| Copycat Blues by Scojo (on 20. July 2024, 06:28) | 18 | 90 % |
| Sarajevo Streets - Bosnian Road Sudoku by Mr.Menace (on 5. August 2024, 09:16) | 17 | 93 % |
