(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 | |
|---|---|---|---|
 | Unboxing (11x11 deconstruction) by jwsinclair (on 13. December 2024, 20:15) | 76 |  96 % |
| 1K Sums by mathpesto (on 20. April 2022, 02:41) | 64 | 99 % |
| UFO (RSL, Entropy) by Mad-Tyas (on 4. November 2024, 00:09) | 76 | 92 % |
| Chaos Construction: Corridors by vidarino (on 1. January 2022, 14:24) | 69 | 97 % |
| Equal Sudoku II by Realshaggy (on 29. April 2013, 12:23) | 74 | 94 % |
| Steamed 'Bans (chaos construction with region sum clues) by SkepticalMario (on 5. September 2024, 00:00) | 76 | 97 % |
| Renban Snakes by Chad (on 16. September 2024, 03:37) | 85 | 94 % |
| Vice Versa (Region Sum Lines Sudoku) by Mr.Menace (on 23. June 2023, 09:30) | 91 | 93 % |
| Compression by Jay Dyer (on 1. September 2024, 21:33) | 94 | 97 % |
| Nonconsecutive Renban by Phistomefel (on 9. February 2022, 20:46) | 116 | 97 % |
| Chaos Construction: Thermo Knots by Myxo (on 18. January 2025, 12:31) | 122 | 96 % |
| Tapa Distiller by yureklis (on 18. August 2009, 21:08) | 49 | 94 % |
| 4 Gleiche by Luigi (on 1. October 2009, 17:10) | 39 | 91 % |
| Das versteckte Rätsel by Luigi (on 18. March 2010, 07:39) | 14 | 92 % |
| Verflixtes ABCtje by ibag (on 28. September 2011, 16:55) | 38 | 95 % |
| April ABCtjes Monat (3) - ABCtje mit und ohne X by Richard (on 20. April 2012, 12:00) | 38 | 92 % |
| Wichtelkalender 2014 - September: Materie-Antimaterie-Rundwege by Statistica (on 1. September 2014, 00:00) | 40 | 98 % |
| Japanischer Summen-Rundweg 2358 (1) by Uhu (on 2. May 2017, 21:10) | 55 | 98 % |
| OSTERN - Buchstabenrätsel by DocLogic (on 31. March 2020, 22:50) | 34 | 92 % |
| Two Sum Sudoku Finale - With Only One Numerical Clue! by ProwlingTiger (on 1. May 2020, 21:35) | 45 | 98 % |
