(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 | |
|---|---|---|---|
 | Meidjuluk N=15 by PrimeWeasel (on 29. September 2023, 16:16) | 35 |  100 % |
| Memento Regem by LeaVulpina (on 10. March 2024, 00:23) | 35 | 93 % |
| Whispering Negativity by yttrio (on 29. June 2024, 01:10) | 38 | 94 % |
| Recoil: No Longer an Introduction by damasosos92 (on 17. March 2025, 18:09) | 33 | 95 % |
| Whispers of Doom 4 by NurglesGift (on 12. December 2025, 18:56) | 79 | 95 % |
| RAT RUN 19: Brainwaves by marty_sears (on 18. December 2024, 01:00) | 756 | 97 % |
| sphinx of black quartz by aqjhs (on 4. October 2024, 01:40) | 114 | 94 % |
| Februar Prim-Monat (3) - Prim Killer (B) by Richard (on 10. February 2012, 12:00) | 65 | 91 % |
| Sudoku Variants Series (288) - Battlefield Sudoku by Richard (on 30. September 2020, 00:00) | 70 | 97 % |
| Some Zippers Somedoku by blackjackfitz (on 16. April 2024, 01:59) | 67 | 98 % |
| Cacophony by zetamath (on 5. August 2021, 18:19) | 94 | 95 % |
| Dude where's my XV? by PetLov (on 6. February 2021, 21:06) | 33 | 92 % |
| Battenburg Killer by MavericksJD (on 12. June 2021, 14:06) | 29 | 93 % |
| Blast Off (Region Sum Killer Diagonal) by tallcat (on 9. June 2023, 20:18) | 99 | 97 % |
| Happy Birthday to Naomi by Fool on Hill (on 31. March 2024, 13:51) | 30 | 96 % |
| double negative by arctan (on 24. September 2024, 22:02) | 29 | 95 % |
| Balance by Scojo (on 3. October 2024, 21:31) | 59 | 95 % |
| The Great River by Blobz (on 23. December 2024, 16:00) | 221 | 95 % |
| Sudoku Variants Series (276) - Taxi Ride Sudoku by Richard (on 8. July 2020, 00:00) | 77 | 92 % |
| Sudoku Variants Series (315) - Summing Up Sudoku by Richard (on 7. April 2021, 00:00) | 77 | 95 % |
