(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 | |
|---|---|---|---|
 | Antiknight Thermo Sudoku by dgreenspan (on 22. July 2020, 22:40) | 49 |  93 % |
| Star Nurikabe N± by BenceJoful (on 2. October 2021, 02:24) | 29 | 94 % |
| Whose Line is it Anyway? (Region Sum, Renban, Global Entropy) by Chefofdeath (on 16. June 2024, 18:21) | 35 | 93 % |
| Wichtel 2013 (8): Professor Kropkis Zahlenkabinett by wichtel (on 9. April 2014, 12:30) | 72 | 98 % |
| Sum Amount of Trouble by Tyrgannus (on 20. August 2023, 00:08) | 93 | 95 % |
| JAMES BOND - Buchstabenrätsel by DocLogic (on 13. January 2020, 18:00) | 39 | 91 % |
| Perfect Squares by ICHTUES (on 23. January 2022, 06:00) | 20 | 91 % |
| Six dots by Lutterot (on 18. May 2023, 22:46) | 38 | 91 % |
| Quiet Self-Reflection by Nordy (on 16. February 2025, 08:30) | 57 | 99 % |
| Loses Kalenderblatt April 2019 (1/2) by April (on 1. April 2019, 00:00) | 28 | 95 % |
| Extreme measures (Parity killer/little killer) by sujoyku (on 24. August 2023, 15:00) | 29 | 93 % |
| Sandwich-Sudoku mit Average Arrows by glum_hippo (on 18. April 2021, 06:00) | 64 | 100 % |
| Irregular Migraine No7 by TinkerTroy (on 1. May 2023, 03:37) | 39 | 95 % |
| Doppelter Rundweg by SilBer (on 4. July 2009, 11:21) | 82 | 95 % |
| The Fountain by Tobias Brixner (on 14. October 2023, 11:49) | 97 | 96 % |
| Happy Holidays #3: Wassailing by Big Tiger (on 9. December 2020, 00:00) | 17 | 100 % |
| A Meandering Path by 10feet (on 6. July 2021, 06:11) | 35 | 94 % |
| Two Faced Coin - Doubling Lines Twist by purpl (on 16. September 2021, 17:59) | 15 | 92 % |
| x-sums and n-cycles by mathpesto (on 7. January 2022, 03:37) | 14 | 96 % |
| Beehive [Hexagonal Akari RGB] by wisty (on 27. December 2023, 02:16) | 17 | 96 % |
