(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 | |
|---|---|---|---|
 | Even Trios Killer Sudoku by Quarterthru (on 14. September 2020, 12:00) | 33 |  98 % |
| Short THERM 12+1 by Lisztes (on 13. November 2020, 01:00) | 33 | 90 % |
| BLT by zetamath (on 19. June 2021, 20:30) | 32 | 98 % |
| Irregional by riffclown (on 2. April 2022, 19:21) | 32 | 93 % |
| Prime Party by Realshaggy (on 22. September 2022, 01:17) | 29 | 95 % |
| Variety (6x6 Sudoku Pack) by Florian Wortmann (on 6. June 2024, 12:56) | 36 | 97 % |
| Key West (Nurikabe/Fillomino) by The Book Wyrm (on 7. August 2025, 16:50) | 31 | 100 % |
| Thermography by arbitrary (on 12. December 2023, 16:22) | 76 | 95 % |
| Counting Reflections by Jolly Rogers (on 18. September 2025, 18:35) | 79 | 95 % |
| Stolen Numerals XVII by NurglesGift (on 15. July 2024, 16:24) | 130 | 97 % |
| Koralle (5) by Uhu (on 8. November 2020, 11:15) | 38 | 91 % |
| Negativity by jwsinclair (on 31. January 2022, 22:13) | 42 | 96 % |
| Juggernaut by Andrewsarchus (on 23. October 2022, 22:20) | 43 | 92 % |
| Duppels by ICHTUES (on 20. August 2023, 07:21) | 40 | 91 % |
| More Unique Arrows by Jolly Rogers (on 28. December 2025, 11:51) | 84 | 95 % |
| Entropy miracle 9 by fractalminding (on 20. March 2026, 12:12) | 44 | 91 % |
| 3 Star Star Battle: Skirmish in the Horsehead Nebula by Thorsby (on 3. September 2020, 00:01) | 48 | 98 % |
| Kill Between The Lines by Djmelee3000 (on 29. September 2020, 02:39) | 45 | 93 % |
| Arrow Sudoku by KNT (on 17. April 2022, 05:46) | 100 | 96 % |
| Unique Killers by Yawnus (on 24. February 2023, 11:50) | 54 | 96 % |
