(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 | |
|---|---|---|---|
 | Hallig-Rundreise by tuace (on 13. April 2015, 00:47) | 43 |  100 % |
| Sandwich Sudoku by kolot (on 15. July 2021, 18:33) | 33 | 95 % |
| Japanese Sums #2: Killer Cages Fillomino by lerroyy (on 3. March 2023, 14:29) | 15 | 98 % |
| Circled Killers by SparkNights (on 12. December 2023, 15:11) | 33 | 96 % |
| Chaos In Frankfurt! (Secret Satan 2023) by Niverio (on 1. January 2024, 17:25) | 35 | 100 % |
| Working Nine To Five by fjam (on 8. January 2024, 20:03) | 16 | 94 % |
| Bank Vault by mormagli (on 5. June 2024, 19:45) | 15 | 94 % |
| Disconnected Counting Chaos by wooferzfg (on 9. June 2024, 05:16) | 30 | 96 % |
| Double-Crosser Deconstruction by Christounet (on 12. July 2024, 00:00) | 14 | 100 % |
| There is still life in my sandwich... by Sktx (on 15. May 2021, 00:49) | 14 | 94 % |
| Heart Breaker (Arrow Sudoku) by FryTheGuy (on 27. May 2021, 03:36) | 14 | 92 % |
| 4D Arrow Sudoku by FryTheGuy (on 6. July 2021, 11:20) | 13 | 98 % |
| Japanese Nurikabe (2) by KNT (on 6. September 2022, 02:52) | 54 | 100 % |
| Mission Improbable by XeonRisq (on 5. August 2023, 17:00) | 25 | 98 % |
| Wave Particles by TotallyNormalCat (on 22. April 2021, 19:00) | 62 | 98 % |
| Palindromic Little Killer X Sudoku by SudokuExplorer (on 23. February 2021, 01:00) | 45 | 96 % |
| Region Geometry X by kolot (on 2. June 2022, 00:28) | 38 | 99 % |
| Invisible Thermometers by Nahileon (on 17. May 2023, 12:51) | 46 | 93 % |
| Chaos Construction: Aquarium (2) by KNT (on 23. June 2022, 01:08) | 58 | 100 % |
| Außerirdische Krypto Killer Pyramide by tuace (on 30. April 2014, 20:00) | 23 | 99 % |
