(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 | |
|---|---|---|---|
 | Eternal Life by Sktx (on 20. May 2021, 12:35) | 20 |  100 % |
| Intersections Sudoku by RockyRoer (on 16. July 2021, 14:00) | 20 | 93 % |
| [159] The Sum of All Indexing by W1DEMAN (on 9. November 2022, 09:59) | 21 | 97 % |
| Unendliches Höhlenrätsel (Infinity Cave) by Phistomefel (on 3. April 2023, 20:00) | 25 | 90 % |
| Liar Japanese Sums #3: Renban Square by Niverio (on 8. January 2023, 21:45) | 66 | 98 % |
| The 2-Colour Theorem by starwarigami (on 17. February 2023, 08:46) | 64 | 94 % |
| Inner Square Diagonals by Phistomefel (on 12. August 2024, 13:31) | 92 | 97 % |
| Cageless (X) Killer Sudoku no. 2 by Shinya (on 23. March 2020, 12:58) | 23 | 95 % |
| Compass Sudoku by stephane.bura (on 16. July 2020, 14:54) | 24 | 97 % |
| CTC Tribute Arrow Sudoku by Lizzy01 (on 6. June 2021, 20:37) | 27 | 95 % |
| Broken Square by PotatoHead21 (on 14. August 2021, 08:24) | 22 | 99 % |
| Activated Japanese Sums by RockyRoer (on 12. November 2022, 13:36) | 21 | 95 % |
| The Chained Trio (Between x Lockout x Double Arrow) by Playmaker6174 (on 19. March 2023, 18:23) | 26 | 96 % |
| Arrow Jungle by PotatoHead21 (on 18. August 2023, 11:49) | 24 | 93 % |
| 10-in-9 killer sudoku #3 by Nylimb (on 11. February 2020, 22:35) | 45 | 99 % |
| Japanische Bahnhöfe, Teil 2 by pirx (on 27. May 2020, 13:00) | 25 | 99 % |
| Split Decision by ViKingPrime (on 30. August 2023, 04:42) | 21 | 96 % |
| X Zip Line by antiknight (on 29. November 2023, 19:36) | 52 | 96 % |
| U-Bahn mit Haltestellen III by tuace (on 28. March 2016, 16:22) | 47 | 95 % |
| Temperature (Thermo, Entropy) by Mad-Tyas (on 30. January 2023, 08:22) | 55 | 94 % |
