(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 | |
|---|---|---|---|
 | Breakthrough by Xenonetix (on 3. March 2023, 03:03) | 67 |  97 % |
| Outside Killer U-Bahn by the_cogito (on 8. July 2025, 17:16) | 32 | 99 % |
| Thorny Tie (Killer Deconstruction) by Agent (on 12. July 2022, 09:00) | 57 | 99 % |
| Birefringence by Jay Dyer (on 25. August 2023, 20:46) | 63 | 95 % |
| Lunch box by Qodec (on 18. August 2020, 11:18) | 32 | 96 % |
| Pencil puzzle sudoku hybrid series #5 - Slitherlink killer sudoku by Aspartagcus (on 9. January 2021, 14:48) | 31 | 95 % |
| Antiknight Killer Sudoku by PotatoHead21 (on 15. September 2021, 05:20) | 78 | 99 % |
| Mysterious Boxes by fjam (on 8. January 2023, 16:19) | 25 | 91 % |
| Adventskalender 2023, Türchen 21 - Lügende Passierscheine by Zzzyxas (on 21. December 2023, 07:00) | 26 | 98 % |
| Killer Sudoku - Twirl by Phistomefel (on 6. December 2020, 11:18) | 73 | 98 % |
| Negators by mathpesto (on 20. August 2022, 00:41) | 53 | 96 % |
| 2T1L by ICHTUES (on 11. September 2022, 06:00) | 70 | 96 % |
| Wichtel 2015 (12 und Schluss): Hommage an eine Künstlerin by wichtel (on 18. July 2016, 21:50) | 34 | 96 % |
| Puffer Fish by Qodec (on 28. November 2020, 22:05) | 48 | 98 % |
| Suguru Chaos Deconstruction #3: Whispering Palindromes by mathpesto (on 20. February 2022, 16:27) | 110 | 97 % |
| 3D2Y by udukos (on 9. November 2024, 20:45) | 39 | 97 % |
| Caudal Autotomy by DadJokes (on 19. August 2022, 21:11) | 28 | 97 % |
| Cryptic Coin (Arrow Kropki Sudoku) (ft. Tyrgannus) by Agent (on 9. September 2022, 09:00) | 69 | 99 % |
| Purple vs Green (Entropy Sudoku) by Mad-Tyas (on 4. April 2023, 10:14) | 39 | 93 % |
| Matchaluck (A Meidjuluk N=15 Variant) by PrimeWeasel (on 11. October 2023, 11:41) | 23 | 100 % |
