Here is my crack for version 0.17.0 of Seaside Mystery.
After launching the game and it finishes loading to the main menu, it should automatically do everything and say "Account Linked" in green. You can now save and load games as usual.
Do feel free to
@Me if any game updates come out and the crack doesn't continue working, or some other issue with it.
There is a more detailed readme.txt but it is quite self-explanatory, basically just put the .dll file next to the game's Seaside Mystery.exe file and it will work automatically.
Edit: If you are exhibiting any issues with this crack, or are still running Windows 7.
Please checkout my alternative crack here-
https://f95zone.to/threads/seaside-mystery-v0-17-cracked-kst.68787/post-10235191