(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 | |
|---|---|---|---|
 | Ambiguity (X-Sums/Numbered Rooms) by udukos (on 5. July 2022, 13:25) | 67 |  97 % |
| Thermo + Killer + Anti-Knight by stimim (on 30. July 2020, 17:38) | 100 | 98 % |
| Foghqwhgads by ThePedallingPianist (on 9. February 2023, 23:55) | 68 | 96 % |
| Striped snake (halvers and doublers) by Lizzy01 (on 23. May 2025, 14:06) | 27 | 94 % |
| Colorimetry (Four Color Pentomino Sums) by Agent (on 19. August 2025, 09:00) | 55 | 97 % |
| Thermo Space Force by PotatoHead21 (on 31. May 2021, 03:51) | 44 | 95 % |
| Recurring Nightmares by Jay Dyer (on 16. October 2022, 01:00) | 41 | 97 % |
| Escalation by Celery (on 12. September 2023, 22:31) | 51 | 94 % |
| Chaos All Over by wuc (on 12. April 2025, 11:49) | 83 | 95 % |
| Propellers by fritzdis (on 6. March 2021, 15:35) | 56 | 97 % |
| Bowser's Castle (Arrow Sudoku) by emmettcito (on 9. April 2021, 12:58) | 97 | 99 % |
| Kropkiflotte auf hoher See II by Luigi (on 30. October 2014, 13:51) | 14 | 93 % |
| Cyclic Thermo Sudoku by trivial171 (on 29. April 2020, 03:43) | 15 | 93 % |
| Killer Construction by ahaupt (on 12. June 2020, 21:33) | 65 | 99 % |
| Tangled Arrows (Arrow sudoku) by Aspartagcus (on 23. October 2020, 23:32) | 16 | 95 % |
| 4D Thermo Sudoku by FryTheGuy (on 27. July 2021, 17:13) | 14 | 95 % |
| Killocator by starwarigami (on 27. October 2021, 10:15) | 58 | 98 % |
| High f**e! by filuta (on 30. March 2022, 15:29) | 47 | 96 % |
| X-Ray Vision (Yin Yang X-Sums Sudoku) by Agent (on 6. September 2022, 09:00) | 74 | 98 % |
| Double Time by shinggaming (on 7. March 2023, 20:16) | 15 | 93 % |
