(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 | |
|---|---|---|---|
 | 13 by Phurba (on 13. December 2020, 15:59) | 26 |  93 % |
| Palindrome Killer by MavericksJD (on 6. January 2021, 11:12) | 26 | 91 % |
| Ratio (-) Arrow Sudoku by Florian Wortmann (on 10. April 2022, 16:06) | 23 | 90 % |
| Floodwaters by Jay Dyer (on 9. July 2022, 00:45) | 68 | 97 % |
| Pigeonhole [Renban, Kropki] by Miky (on 26. March 2023, 10:21) | 70 | 91 % |
| Oil Spill by Mayamor (on 20. April 2023, 14:35) | 27 | 92 % |
| The Magic Column by marty_sears (on 26. April 2023, 10:26) | 27 | 97 % |
| Octopus Knight (Octopus Rules, Chess Lines) by gdc (on 10. June 2024, 15:51) | 23 | 93 % |
| Rudolph? by ThePedallingPianist (on 22. November 2022, 23:38) | 68 | 95 % |
| Mehrdeutige Rätsel - Rundweg 2 by uvo (on 22. February 2017, 10:01) | 44 | 95 % |
| Habitat 67 by sfushidahardy (on 15. October 2024, 18:35) | 39 | 98 % |
| Counting Calories by marty_sears (on 3. June 2024, 07:30) | 107 | 96 % |
| Domino Effect by vitaminz (on 12. April 2024, 15:49) | 58 | 97 % |
| Every Third Knight by JeremyDover (on 4. February 2022, 17:00) | 86 | 94 % |
| 10-in-9 killer sudoku #4 by Nylimb (on 21. February 2020, 17:48) | 36 | 98 % |
| Six-pack Linked Puzzles by Genomico (on 17. September 2020, 00:51) | 56 | 97 % |
| Koralle (5) by Uhu (on 8. November 2020, 11:15) | 35 | 91 % |
| Qarpet Beater by Qodec (on 14. November 2020, 14:59) | 56 | 94 % |
| Sandwich Cosmic Sudoku - Follow the North Galaxy by DiMono (on 27. December 2020, 21:37) | 18 | 93 % |
| X-Sums Fillomino #3 (4x4x4) by Jesper (on 15. March 2021, 19:53) | 34 | 100 % |
