(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 | |
|---|---|---|---|
 | Japanese Sums #3: Reef by Myxo (on 17. May 2023, 21:10) | 59 |  95 % |
| The Engine (Killer sudoku) by sujoyku (on 19. July 2025, 16:54) | 136 | 97 % |
| Coordinate Arrows (Sudoku) by Piatato (on 13. February 2022, 18:17) | 134 | 96 % |
| Hochhaussummen-Sudoku [5] Killer by Errorandy (on 29. April 2020, 16:00) | 23 | 97 % |
| Lend Me Your Eyes by RockyRoer (on 17. November 2020, 01:46) | 23 | 97 % |
| Time capsule by Testarossa (on 22. September 2021, 15:41) | 24 | 93 % |
| Skyscrapers Sudoku by Qodec (on 11. December 2021, 11:33) | 68 | 92 % |
| Curvedoku by chameleon (on 1. July 2022, 13:23) | 25 | 100 % |
| Ruined Arch by Jay Dyer (on 24. July 2022, 19:30) | 26 | 97 % |
| Torque by randall (on 16. October 2022, 07:21) | 25 | 93 % |
| Ambiguous Little Killer + X-Sums Clues by Jeet Sampat (on 27. October 2022, 16:07) | 26 | 96 % |
| Limitless Potential #2: The Wanderer's Path by Playmaker6174 (on 12. May 2023, 16:49) | 23 | 95 % |
| Can I "borrow" some carrots? by SecondBlue (on 20. December 2024, 02:54) | 24 | 96 % |
| daft zebras jump quickly by aqjhs (on 28. November 2025, 01:23) | 28 | 93 % |
| Orchid's Revenge by Abdul the Killer (on 1. October 2024, 12:34) | 88 | 96 % |
| Krypto - Tapa by Zzzyxas (on 2. May 2021, 16:29) | 51 | 99 % |
| 12 Arrows, 6 Rows by jovi_al (on 5. January 2022, 05:56) | 54 | 96 % |
| Overkill by Jay Dyer (on 24. August 2022, 17:19) | 96 | 98 % |
| No Idea by rysmyth240 (on 11. April 2021, 17:13) | 78 | 93 % |
| X---V*Parity Quads by NurglesGift (on 18. April 2025, 05:47) | 71 | 96 % |
