(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 | |
|---|---|---|---|
 | Cave Panem (Anti-XV Sandwich) by Phistomefel (on 27. February 2022, 07:22) | 142 |  97 % |
| Metope (Chaos Construction) by tallcat (on 9. December 2023, 08:00) | 112 | 97 % |
| Sudoku Variants Series (326) - Odd-Even Sandwich Sudoku by Richard (on 23. June 2021, 00:00) | 53 | 94 % |
| Xandwich by Qodec (on 4. January 2022, 01:14) | 49 | 96 % |
| Matching by kolot (on 15. November 2021, 05:22) | 77 | 98 % |
| Fibonaccis Fillo-Tapa (Permakultur) by usp (on 4. August 2014, 12:00) | 27 | 93 % |
| Cithara by BIGfoot (on 2. November 2021, 15:38) | 28 | 92 % |
| Entropic Expansion by magnageas (on 25. September 2022, 23:05) | 28 | 99 % |
| Knight's XV by Scruffamudda (on 25. April 2023, 22:38) | 26 | 95 % |
| King Arthur by oxjphs (on 13. August 2023, 06:37) | 59 | 95 % |
| Ambiguity by zetamath (on 8. April 2021, 01:48) | 77 | 96 % |
| Boulder (Fillomino/Heyawake) by mathpesto (on 29. April 2023, 16:15) | 53 | 94 % |
| Inseln mit Hochhäusern, Teil 3 by pirx (on 8. December 2016, 20:00) | 43 | 99 % |
| Differenzen zwischen Summen II by tuace (on 17. August 2018, 13:23) | 44 | 99 % |
| Amtsbeginn in Rätselhausen by Statistica (on 1. December 2019, 09:00) | 23 | 99 % |
| Udukos' breakfast by Qodec (on 14. October 2020, 20:49) | 25 | 95 % |
| Modular Killer by TotallyNormalCat (on 30. January 2021, 00:00) | 25 | 99 % |
| A Symmetry by twototenth (on 1. November 2022, 08:00) | 74 | 98 % |
| Suspicious Dwarf by Myxo (on 22. March 2023, 13:34) | 76 | 94 % |
| Prime Management by Dr Logic (on 21. December 2023, 16:43) | 22 | 91 % |
