(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 | |
|---|---|---|---|
 | Worm on a Stick by ThePedallingPianist (on 20. December 2022, 01:17) | 78 |  92 % |
| Twenty (and) Twenty-Five by Big Tiger (on 26. December 2024, 23:22) | 39 | 95 % |
| Irregular Killer Sudoku 3 by Azure (on 12. April 2025, 09:28) | 40 | 95 % |
| jolly green giant, his arms folded by mellowrobinson (on 11. November 2025, 03:21) | 33 | 99 % |
| One Fish, Two Fish by Blobz (on 13. December 2025, 16:00) | 78 | 95 % |
| 2CT Appreciation (German Whispers thermometer sudoku) by Qodec (on 1. January 2024, 23:34) | 93 | 97 % |
| Six-pack Linked Puzzles by Genomico (on 17. September 2020, 00:51) | 58 | 97 % |
| GraVitron (by Twototenth and Tallcat) by twototenth (on 25. January 2022, 08:00) | 30 | 97 % |
| Chain Link Fence [Arrow Sudoku] by Malrog (on 25. August 2022, 13:36) | 29 | 93 % |
| De l'autre côté... [9x9 mirrored digits] by Christounet (on 5. September 2023, 08:32) | 54 | 99 % |
| Sleeper Cells by Bearded Fool (on 30. August 2024, 12:00) | 36 | 92 % |
| The Diamond Sea (XY Differences Chaos Construction) by tallcat (on 10. May 2025, 06:00) | 202 | 98 % |
| Mysterious Mirrors by marty_sears (on 25. October 2025, 23:49) | 121 | 95 % |
| Criss Cross by FullDeck-Missing (on 19. July 2022, 15:04) | 54 | 93 % |
| RAT RUN 16: Schrödinger's Rat by marty_sears (on 27. November 2024, 01:00) | 653 | 98 % |
| 3etweeN by Qodec (on 17. April 2021, 17:56) | 80 | 98 % |
| Twin chaos sudoku by Richard (on 21. October 2009, 21:48) | 116 | 93 % |
| Past Midnight by Selsted (on 20. October 2020, 17:57) | 24 | 97 % |
| 13 by Phurba (on 13. December 2020, 15:59) | 29 | 93 % |
| Palindrome Killer by MavericksJD (on 6. January 2021, 11:12) | 26 | 91 % |
