(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 | |
|---|---|---|---|
 | Geschenk für pin7guin: Kropki-U-Bahn unter Kropki-Hochhäusern by Zzzyxas (on 6. September 2013, 00:00) | 42 |  99 % |
| A 38 III (toroidal) by tuace (on 28. October 2017, 13:19) | 21 | 99 % |
| Japanische Bahnhöfe, Teil 3 by pirx (on 27. May 2020, 13:00) | 23 | 100 % |
| Crossbeams (Little Killer) by Gliperal (on 7. October 2020, 02:25) | 20 | 97 % |
| Kitchen Nightmare (Sandwich Chaos Construction) by Tacosian (on 14. November 2023, 05:01) | 23 | 99 % |
| Nuriquarium Sudoku by Jay Dyer (on 26. January 2023, 12:46) | 46 | 95 % |
| Balance Loop Sudoku by Gliperal (on 15. December 2021, 21:07) | 44 | 94 % |
| Dichromium (Pentomino Ambiguity) by KNT (on 11. June 2022, 17:22) | 40 | 99 % |
| Enantiodromia (Yin-Yang Chaos Construction, 8x8) by thoughtbyte (on 3. August 2022, 00:05) | 21 | 99 % |
| Serial Duplex by Jay Dyer (on 29. October 2022, 17:46) | 27 | 99 % |
| Roller Coaster Yin Yang Cipher by Piatato (on 26. December 2022, 11:26) | 21 | 100 % |
| Wichtel 2022 (2): Die neue Wichtel-U-Bahn by wichtel (on 6. September 2023, 09:09) | 21 | 98 % |
| Chaos Skyscrapers by JoWovrin (on 17. December 2021, 03:37) | 20 | 97 % |
| Chaos Construction: Stitches by XeonRisq (on 18. February 2022, 01:00) | 19 | 97 % |
| Schrödinger's Deconstruction by mathpesto (on 19. June 2022, 13:57) | 40 | 98 % |
| Region Geometry X by kolot (on 2. June 2022, 00:28) | 36 | 99 % |
| Rainy Night by FryTheGuy (on 6. December 2021, 17:17) | 23 | 98 % |
| The last call by filuta (on 18. April 2022, 17:38) | 21 | 95 % |
| Hell's Coordinates (Sudoku) by Piatato (on 4. January 2023, 13:16) | 17 | 100 % |
| Japanese Sums #1: Killer Cages by lerroyy (on 15. February 2023, 19:52) | 18 | 95 % |
