(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 | |
|---|---|---|---|
 | 2d Wave Particles by zetamath (on 15. July 2021, 18:22) | 28 |  95 % |
| FMTC by Starstorm (on 20. June 2023, 21:21) | 13 | 98 % |
| A Third Loop by mathpesto (on 24. August 2023, 02:34) | 45 | 99 % |
| The Deck of Many Things by ViKingPrime (on 7. September 2023, 20:30) | 13 | 98 % |
| Displacement (Arrow Sudoku) by Phistomefel (on 10. May 2022, 19:07) | 94 | 98 % |
| 10-in-9 Isolation Sudoku by Phistomefel (on 5. April 2020, 12:07) | 41 | 97 % |
| XY-Differences III by glum_hippo (on 14. July 2020, 02:12) | 45 | 92 % |
| Skyscraper Slingshot Sudoku by Piatato (on 2. February 2023, 21:43) | 35 | 100 % |
| Purple vs Green (Entropy Sudoku) by Mad-Tyas (on 4. April 2023, 10:14) | 36 | 92 % |
| Quincies by lerroyy (on 11. June 2023, 19:14) | 36 | 92 % |
| Toutatis by IcyFruit (on 9. May 2024, 14:35) | 39 | 93 % |
| Cavernous Construction by GarlicBredFries (on 5. May 2022, 06:47) | 76 | 98 % |
| Arrows and Palindromes - II by tenaliraman (on 18. April 2021, 21:22) | 26 | 91 % |
| Squares and Circles by Burning Curtains (on 15. August 2021, 20:17) | 43 | 98 % |
| Parasite by XeonRisq (on 10. March 2023, 17:00) | 26 | 92 % |
| Pack of Aces by mormagli (on 8. February 2024, 02:20) | 48 | 99 % |
| Renban Circus by JeffWajes (on 2. September 2024, 18:54) | 51 | 94 % |
| Antiknight Killer Sudoku by PotatoHead21 (on 15. September 2021, 05:20) | 74 | 99 % |
| Vignettes by zetamath (on 18. July 2022, 00:54) | 77 | 99 % |
| Avada Kedavra - A Magic Square Killer by Philipp Huber (on 8. July 2020, 22:38) | 70 | 93 % |
