(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 | |
|---|---|---|---|
 | Killer of the Seas by Piatato (on 9. June 2021, 13:57) | 46 |  99 % |
| Arrows and Dots by kolot (on 21. August 2021, 13:12) | 31 | 94 % |
| Adorable Fury by DiMono (on 5. October 2021, 17:30) | 19 | 94 % |
| The Toppling Tree by fjam (on 9. January 2022, 19:29) | 25 | 99 % |
| Four Unique Ways by kolot (on 30. April 2022, 16:38) | 34 | 92 % |
| Conundrum by Andrewsarchus (on 18. October 2022, 05:46) | 13 | 98 % |
| Deconstruksum [Position Sums Deconstruction] by Christounet (on 26. February 2023, 13:39) | 46 | 100 % |
| Escalation by Celery (on 12. September 2023, 22:31) | 45 | 95 % |
| X-sum, but in Chaos by SparkNights (on 21. September 2023, 06:00) | 37 | 96 % |
| Firework for Entropy No. 50 by Mad-Tyas (on 19. December 2023, 18:19) | 44 | 95 % |
| Sauntering Supernova by Groktilian (on 20. December 2023, 19:55) | 14 | 90 % |
| Return of the killer tomatoes (Shikaku killer) by PrimeWeasel (on 7. January 2024, 17:32) | 32 | 93 % |
| Japanese Sums Fillomino (10x10) by Jesper (on 2. December 2021, 09:41) | 48 | 99 % |
| Irregular Whirlpool by jojo81gaming (on 6. May 2022, 15:33) | 48 | 94 % |
| Cave Battle (15x15) by Jesper (on 20. March 2023, 16:00) | 35 | 99 % |
| Sum 41 - Little Killer / Arrow Sudoku by Mr.Menace (on 6. March 2021, 09:37) | 30 | 96 % |
| Line of Sight Chaos Production (9x9) by RockyRoer (on 4. February 2022, 03:10) | 32 | 100 % |
| Cages Constriction (Slitherlink Chaos Construction Sudoku) by rockratzero (on 8. April 2023, 10:43) | 36 | 94 % |
| Cryptic Skyscrapers (Alphabet Soup) by emmettcito (on 21. March 2021, 00:30) | 30 | 98 % |
| Read Between the Lines (Build Your Own Puzzle) by tallcat (on 8. December 2021, 03:56) | 82 | 100 % |
