(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 | |
|---|---|---|---|
 | Summation U-Bahn Cipher by Agent (on 3. October 2023, 09:00) | 56 |  100 % |
| Chaos Construction: Sightlines by KNT (on 3. June 2022, 07:40) | 135 | 97 % |
| Nurikabe and Chaos by wooferzfg (on 20. February 2023, 02:53) | 71 | 100 % |
| MIA by zetamath (on 24. May 2022, 16:03) | 99 | 98 % |
| Snake Sum Sudoku 5 by Quarterthru (on 11. July 2020, 20:00) | 25 | 97 % |
| Where are the cage totals? - Odd/Even killer sudoku (#5) by Mr.Menace (on 2. February 2021, 10:12) | 32 | 95 % |
| The Devil's Arrow by PotatoHead21 (on 6. June 2021, 06:51) | 21 | 92 % |
| Thonk? by purpl (on 3. May 2022, 00:26) | 28 | 95 % |
| Self-determination by stephane.bura (on 5. September 2022, 15:46) | 82 | 98 % |
| Disambiguation by Flywinged (on 5. February 2023, 01:07) | 22 | 92 % |
| Fillomino Yajilin (10x10) by ns08 (on 8. May 2023, 00:01) | 23 | 95 % |
| Proximity (Renban/Antiknight) by dumediat (on 13. May 2023, 14:29) | 73 | 93 % |
| Sea Level Rise Sudoku by MagnusJosefsson (on 31. March 2024, 18:58) | 20 | 98 % |
| MGC-1326 [Masyu Star Battle] by Christounet (on 17. July 2024, 23:54) | 30 | 95 % |
| Medieval Buffet by Manta-Ray (on 16. September 2024, 14:11) | 31 | 95 % |
| Slitherlinked (Permaculture) by the_cogito (on 10. March 2025, 19:34) | 20 | 97 % |
| Chaos Construction: Liar Japanese Sum (9x9) by Playmaker6174 (on 22. August 2025, 23:00) | 30 | 100 % |
| Lines Lines by SSG (on 17. September 2025, 07:05) | 40 | 93 % |
| The Ones Who Came Before by Manta-Ray (on 30. October 2025, 14:42) | 19 | 98 % |
| Summon by KNT (on 28. December 2025, 14:26) | 29 | 100 % |
