(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 | |
|---|---|---|---|
 | Graffiti: A yajilomino experience (Fillomino/Yajilin) by dumediat (on 22. August 2023, 04:07) | 54 |  98 % |
| Cave / Stations by KNT (on 12. December 2023, 18:15) | 100 | 98 % |
| Roller Coaster in Rätselhausen by Statistica (on 6. December 2016, 06:06) | 45 | 98 % |
| Kill-o-meter by Jreg (on 12. January 2023, 07:35) | 15 | 93 % |
| How does this even work? - Odd/Even Killer sudoku by Mr.Menace (on 28. May 2024, 20:45) | 20 | 93 % |
| Mellow Mancala by heliopolix (on 13. July 2024, 00:00) | 16 | 91 % |
| Wichtels (später) Rätselsommer 2024 (10): Yingu Jam by wichtel (on 3. October 2024, 20:23) | 17 | 92 % |
| at the vortex spot by aqjhs (on 2. October 2025, 23:58) | 16 | 96 % |
| Pealates by Oddlyeven (on 3. May 2026, 14:02) | 17 | 93 % |
| Copycat Chaos by Andrewsarchus (on 3. May 2026, 09:47) | 20 | 95 % |
| Twin Chaos Sudoku II by Richard (on 30. March 2012, 12:00) | 77 | 91 % |
| Castle Woku (Castle Wall/Sudoku) by Wessel Strijkstra (on 16. December 2022, 16:49) | 40 | 99 % |
| Anti-knight Thermo Sudoku #2 - Thermocouples by RSP (on 19. July 2020, 19:57) | 117 | 99 % |
| Killer Sudoku #1 (‘The Portal’) by PixelPlucker (on 12. November 2020, 09:48) | 25 | 91 % |
| Killer of the Seas by Piatato (on 9. June 2021, 13:57) | 65 | 99 % |
| Mysterious Couple by sujoyku (on 19. November 2022, 13:20) | 26 | 97 % |
| Indianapolis by ICHTUES (on 13. November 2022, 06:00) | 56 | 94 % |
| Addierter Überlappungssudoku III by Richard (on 14. May 2010, 12:00) | 85 | 96 % |
| Your ways are numbered (broken 159, killer, disjoint) by Chilly (on 24. January 2022, 00:29) | 30 | 94 % |
| huisgenoot gezocht by aqjhs (on 8. December 2025, 01:59) | 33 | 99 % |
