(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 | |
|---|---|---|---|
 | Extra Tall Skyscrapers by yttrio (on 4. August 2023, 20:04) | 42 |  97 % |
| All Truths, All Lies by dodomos (on 25. October 2023, 10:00) | 48 | 91 % |
| Thermography by arbitrary (on 12. December 2023, 16:22) | 74 | 95 % |
| Quantum Moon by heliopolix (on 2. June 2024, 00:00) | 16 | 90 % |
| Yin Doubles Yang (Killer + Yin Yang) by damo_89 (on 8. June 2024, 17:24) | 150 | 97 % |
| Incongruity by zetamath (on 20. August 2024, 20:36) | 39 | 97 % |
| Sudoku Variants Series (033) - Little Killer by Richard (on 15. July 2014, 00:00) | 164 | 95 % |
| Raw Spaghetti (equal sums lines sudoku) by Aspartagcus (on 23. June 2022, 23:19) | 69 | 97 % |
| U-Bahn unter Hochhäusern (Teil 7) by Zzzyxas (on 5. May 2012, 18:21) | 52 | 99 % |
| Killer Sudoku: The Fearsome Twelves by Playmaker6174 (on 1. December 2022, 19:43) | 61 | 97 % |
| Chaos Control by Scojo (on 15. April 2023, 01:59) | 58 | 94 % |
| Fraction Party by sujoyku (on 12. September 2023, 19:46) | 58 | 97 % |
| Yin Yang Arrows by yttrio (on 13. October 2023, 23:06) | 112 | 98 % |
| Six 6x6-sudoku pack by Qodec (on 26. June 2021, 23:10) | 51 | 98 % |
| Shady Combination #1: Cave, Pentominos, Slitherlink, Snake by Myxo (on 9. January 2023, 15:33) | 41 | 99 % |
| whisperwhisperwhisperwhisper by twototenth (on 18. January 2022, 08:00) | 85 | 94 % |
| Mnmle Mgntplttn by berni (on 11. April 2016, 14:13) | 36 | 98 % |
| PYRAMIDE - Buchstabenrätsel / Letter puzzle by DocLogic (on 3. February 2020, 18:21) | 36 | 95 % |
| Qnight by tsc (on 23. October 2021, 10:13) | 42 | 97 % |
| Position Sums: Fillomino (11x11) by ONeill (on 20. October 2022, 05:59) | 38 | 100 % |
