(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 | |
|---|---|---|---|
 | Golden Palindromes by MathGuy_12 (on 23. September 2025, 03:28) | 125 |  97 % |
| Sudoku Variants Series (375) - Odd-Even Thermometers by Richard (on 13. July 2022, 02:00) | 115 | 96 % |
| U-Bahn mit gemischten Hinweisen (Teil 1) by Zzzyxas (on 28. December 2019, 13:32) | 51 | 99 % |
| Path with opposite crosses (novel puzzle type) by SebastianSimon (on 23. December 2020, 14:58) | 24 | 96 % |
| Galaga by tenaliraman (on 16. September 2022, 10:35) | 58 | 95 % |
| Double Dragon (ft. Piatato) by Nordy (on 3. December 2022, 08:00) | 51 | 97 % |
| Hybrid Star Battle Series (014) - Double Back by BenceJoful (on 13. April 2023, 16:17) | 31 | 94 % |
| Thermoconstrictor by HalfBakedLunatic (on 27. October 2023, 19:20) | 66 | 93 % |
| Goldenrod weathercock by NicoD (on 25. April 2025, 05:30) | 57 | 96 % |
| $10 Modular Housing by mellowrobinson (on 3. December 2025, 16:38) | 29 | 94 % |
| Thermo Sudoku by Realshaggy (on 26. May 2020, 22:31) | 92 | 94 % |
| The Butterfly Effect - Region Sum Lines Sudoku by Mr.Menace (on 28. February 2022, 20:11) | 103 | 97 % |
| Transmission by Phistomefel (on 18. January 2023, 17:39) | 289 | 97 % |
| Knightmare on Mount Pleasant Avenue by HalfBakedLunatic (on 25. March 2024, 22:21) | 98 | 95 % |
| Ping Pong by antiknight (on 19. January 2025, 19:37) | 98 | 95 % |
| Even The Odd Arrow by tzael (on 28. July 2020, 09:26) | 30 | 91 % |
| Astronomic Squares Sudoku by Philipp Huber (on 7. August 2020, 10:35) | 27 | 90 % |
| Slingshot Sudoku - Confrontation by stephane.bura (on 26. August 2020, 20:00) | 28 | 96 % |
| Singularity Fever [Thermo] by Miky (on 14. June 2021, 20:47) | 31 | 96 % |
| Arrow Dynamics by SSG (on 23. June 2021, 07:58) | 35 | 97 % |
