(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 | |
|---|---|---|---|
 | Killomino Sudoku by Phistomefel (on 10. June 2021, 03:54) | 94 |  99 % |
| Summation U-Bahn #5: Sorted Clues by Agent (on 22. October 2024, 09:00) | 37 | 97 % |
| Lockdown by Prof.Dori (on 29. September 2025, 13:12) | 83 | 95 % |
| Rivers and Islands Sudoku #2 (hard) by matt383 (on 27. May 2020, 14:12) | 39 | 96 % |
| Greedy Cages Sudoku by Phistomefel (on 3. May 2022, 22:41) | 75 | 99 % |
| The Elephant (Renban, Entropy) by Mad-Tyas (on 3. January 2023, 11:37) | 39 | 97 % |
| Zodiac Project: the year of the dög by aqjhs (on 20. November 2025, 00:55) | 35 | 98 % |
| String Theory (Renban Incomplete Arrow) by tallcat (on 19. July 2021, 17:03) | 28 | 96 % |
| Sunken Treasure Chaos Construction by Schwupel (on 24. July 2022, 18:58) | 28 | 97 % |
| Crypto Japanese Cave-Bahn by KNT (on 18. January 2023, 07:32) | 54 | 98 % |
| Utterly A Maze Thing by fjam (on 12. March 2023, 19:01) | 28 | 95 % |
| Regional Scores by Big Tiger (on 16. December 2023, 13:45) | 30 | 98 % |
| Medieval Upheaval 4 by Nordy (on 24. June 2024, 08:00) | 89 | 97 % |
| Three-legged Dog by Abdul the Killer (on 9. November 2022, 19:45) | 55 | 90 % |
| Parity Party X - "Sir Launcelot" by glum_hippo (on 7. June 2020, 06:52) | 23 | 92 % |
| Spiral Galaxy Sudoku with clues by PrimeWeasel (on 13. November 2021, 16:55) | 20 | 97 % |
| Binary Quantum Void by DadJokes (on 13. October 2022, 19:14) | 26 | 94 % |
| Crystallizer (Filloku #7) by mormagli (on 30. January 2024, 17:31) | 24 | 99 % |
| Chocona Mall by Jay Dyer (on 16. August 2024, 21:19) | 24 | 93 % |
| Klein's Foggy Glasses by DubiousMobius (on 3. October 2024, 21:43) | 27 | 96 % |
