(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 | |
|---|---|---|---|
 | Galactic Skirmish (Spiral Galaxy, Star Battle, Killer Sudoku) by AnalyticalNinja (on 1. February 2023, 02:21) | 97 |  95 % |
| Split Connections (U-Bahn + Loop) by Nordy (on 31. July 2023, 08:00) | 29 | 96 % |
| Sagittarius (Killer Sudoku ft. jovi_al) by purpl (on 7. October 2022, 01:39) | 80 | 94 % |
| Renban ModE - Little Killer/Renban sudoku by Mr.Menace (on 29. May 2021, 17:43) | 42 | 98 % |
| Two Sums by CaptZebraCakes (on 26. January 2024, 20:57) | 42 | 96 % |
| Vertigo Yajilin #1 by Piatato (on 10. April 2024, 00:37) | 40 | 99 % |
| Thermo Miracle Sudoku by SudokuExplorer (on 7. July 2020, 18:05) | 102 | 90 % |
| Negative X plus V by TheGreatGoatsbie (on 7. August 2024, 20:10) | 118 | 94 % |
| Ignition! (Thermo) by Blashyrkh (on 19. October 2024, 14:41) | 116 | 94 % |
| Endemic by NicoD (on 13. February 2026, 05:30) | 60 | 92 % |
| Pseudoscience by marty_sears (on 7. February 2024, 19:54) | 222 | 96 % |
| Sudoku Variants Series (351) - Double Trouble Killer Sudoku by Richard (on 15. December 2021, 00:00) | 78 | 96 % |
| Pac-Man Sudoku by mathpesto (on 10. June 2023, 04:50) | 130 | 95 % |
| Jetzt gehts rund, Takashi by tuace (on 6. July 2014, 10:30) | 49 | 99 % |
| LM 2018 Countdown: A 38 (1) by tuace (on 2. June 2018, 09:06) | 44 | 95 % |
| Parity Runs #3: Skyscraper by Madmahogany (on 10. June 2020, 20:17) | 45 | 94 % |
| Azulejos by ndsurgenor (on 15. March 2022, 14:42) | 37 | 96 % |
| The Knight and the Knave (Legit/Liar Sudoku) by mathpesto (on 16. August 2022, 23:13) | 82 | 97 % |
| Chaos Fillomino - Border Gaps #1 by Mark Sweep (on 7. December 2022, 10:00) | 38 | 99 % |
| A Killer Palindrome Sudoku by by81996672 (on 26. December 2023, 08:35) | 39 | 93 % |
