(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 | |
|---|---|---|---|
 | ZandwYch by ICHTUES (on 10. September 2023, 06:00) | 31 |  97 % |
| Negative Energy by jojo81gaming (on 26. January 2024, 01:28) | 14 | 98 % |
| Augur's gift (Japanese sums/Mean mini/Kropki) by dumediat (on 24. May 2024, 03:09) | 32 | 97 % |
| We Have Palindromes at Home by Kafkapharnaum (on 7. July 2024, 07:13) | 13 | 90 % |
| GCF by RockyRoer (on 14. February 2025, 14:39) | 13 | 96 % |
| Stabelle by ICHTUES (on 14. August 2023, 11:00) | 97 | 97 % |
| Noch ein 3D Rundweg by Calavera (on 31. December 2009, 05:49) | 61 | 98 % |
| Rudolph? by ThePedallingPianist (on 22. November 2022, 23:38) | 70 | 95 % |
| LM Gapped Kakuro by yureklis (on 3. January 2011, 23:50) | 87 | 95 % |
| Schlangennest — mal anders by glum_hippo (on 19. March 2022, 16:57) | 41 | 96 % |
| Minister of Primes (featured on CtC) by Mountainfarmer (on 6. August 2022, 11:19) | 38 | 94 % |
| Center of Attention (Qodec's Tribute Puzzle) by Playmaker6174 (on 4. November 2022, 09:42) | 74 | 97 % |
| Growing Up by the_cogito (on 22. December 2022, 19:43) | 36 | 99 % |
| Duppels by ICHTUES (on 20. August 2023, 07:21) | 36 | 92 % |
| Sudoku Variants Series (375) - Odd-Even Thermometers by Richard (on 13. July 2022, 02:00) | 100 | 96 % |
| Time to Think Outside the Box by zegres (on 1. March 2022, 06:49) | 52 | 98 % |
| Intersections by IcyFruit (on 8. February 2024, 14:27) | 118 | 98 % |
| Japanische Summen mit Querverweisen by ibag (on 23. December 2011, 21:31) | 70 | 98 % |
| German Whispers Sandwich Sudoku by Jesper (on 4. July 2020, 11:47) | 76 | 96 % |
| Dense Populations by Mark Sweep (on 5. March 2021, 10:00) | 22 | 97 % |
