(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 | |
|---|---|---|---|
 | Patches and Stitches by Sktx (on 15. November 2021, 13:00) | 30 |  97 % |
| Unique Value Deconstruction by sfushidahardy (on 27. June 2024, 18:13) | 29 | 95 % |
| A Third Loop by mathpesto (on 24. August 2023, 02:34) | 49 | 99 % |
| WPC 2016 Training - Pentominos by uvo (on 12. July 2017, 15:33) | 39 | 98 % |
| Palindrome Killer Sudoku by udukos (on 8. August 2020, 23:02) | 41 | 94 % |
| Antiknight Between Lines by Gliperal (on 12. May 2021, 04:19) | 41 | 97 % |
| Witchcraft by PotatoHead21 (on 25. November 2021, 21:56) | 39 | 98 % |
| Extraterrestrial Tripleblock with X-Sums by KNT (on 27. May 2023, 16:45) | 36 | 100 % |
| Matter by ThePedallingPianist (on 12. August 2023, 00:38) | 22 | 92 % |
| Build-Your-Own Kropki Sudoku by The Book Wyrm (on 15. January 2024, 20:58) | 52 | 95 % |
| Position Sums mit Average Arrows by glum_hippo (on 27. December 2024, 16:59) | 17 | 98 % |
| Entropical Pairadise (Pairrow, Yin Yang) by DubiousMobius (on 23. January 2025, 16:44) | 58 | 98 % |
| Fillomino-ish Killer Sudoku by SirWoezel (on 25. November 2020, 16:21) | 55 | 99 % |
| The Red and the Black (Anti-King Arrow) by tallcat (on 18. October 2021, 15:41) | 52 | 93 % |
| Three of Diamonds by zetamath (on 20. February 2023, 16:07) | 54 | 93 % |
| Marco Polo (Loop Deconstruction) by Agent (on 6. June 2023, 09:00) | 97 | 98 % |
| Seesaw (Killer Only Sudoku) by Celery (on 10. December 2023, 22:34) | 54 | 98 % |
| Too Close For Comfort by Niverio (on 3. March 2024, 16:11) | 53 | 96 % |
| Post Office Panic! by tesseralis (on 4. July 2022, 10:14) | 80 | 98 % |
| Kill Kill (Doubler Killer) by ICHTUES (on 28. August 2022, 06:00) | 61 | 98 % |
