(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 | |
|---|---|---|---|
 | Cold Sauerkraut (Nabner Thermo Sudoku) by Silverstep (on 24. August 2023, 17:47) | 28 |  91 % |
| De l'autre côté... [9x9 mirrored digits] by Christounet (on 5. September 2023, 08:32) | 50 | 99 % |
| Spring Latch by Qodec (on 13. October 2023, 22:07) | 68 | 97 % |
| MeidjulOOp ! [Meidjuluk N=18; Loop] by Christounet (on 25. October 2023, 21:54) | 33 | 98 % |
| Two Trips by igniteice (on 1. January 2024, 00:48) | 52 | 95 % |
| GP24 Leftover: Japanische Summen + Magnetplatten by ibag (on 24. March 2024, 20:24) | 33 | 99 % |
| Pseudo Cluedo by marty_sears (on 6. April 2024, 01:13) | 72 | 97 % |
| Renban shifted x-sums by Lizzy01 (on 20. July 2024, 22:55) | 12 | 92 % |
| They check in, but they don't check out by Strosahl (on 3. October 2024, 06:13) | 24 | 93 % |
| Milestones by marty_sears (on 5. October 2024, 19:14) | 111 | 99 % |
| Sudoku Variants Series (284) - Isolation Killer Sudoku by Richard (on 2. September 2020, 00:00) | 92 | 97 % |
| Rivets by XeonRisq (on 12. June 2023, 04:00) | 68 | 96 % |
| Thermometer-Hochhäuser, 8x8 by pirx (on 12. December 2013, 18:08) | 61 | 95 % |
| Tapa-Höhle 1 by usp (on 13. March 2015, 00:00) | 55 | 91 % |
| Reign of Cassiopeia by Tyrgannus (on 24. June 2022, 06:25) | 59 | 95 % |
| Rundweg andersrum 3 by Menxar (on 14. September 2009, 10:10) | 47 | 95 % |
| Stretch marks by Qodec (on 23. March 2022, 21:37) | 95 | 98 % |
| Shenanigans by Jay Dyer (on 9. May 2023, 17:11) | 138 | 98 % |
| Summenbild-Rundwegrätsel (1) by Uhu (on 3. November 2020, 20:29) | 41 | 98 % |
| Maximus Unique by Klvsched (on 24. June 2024, 14:00) | 95 | 96 % |
