In the game there are a grid of hearts, you have to match the hearts by swapping them. The hearts will be matched if a line of 3 or more hearts of the same kind are there. When some hearts are matched, new hearts will be created. You need to match hearts as quickly as possible in order to advance to the next level.
You don't need Adobe Flash player which must be desinstalled of your computer because the support of Adobe has stopped on December 31, 2020. For more information, you can read the page on the end of Flash and the start of Ruffle the Flash emulator in Javascript for modern updated navigators.
Many games are not playable with Ruffle and generate a warning message:
"This content is not yet supported by the Ruffle emulator and will likely not run as intended."
Useless to clic on the "Run anyway" button, the game will be not functional. These games will be progressively deactivate awaiting a future evolution of emulator.
Other games start but don't work well. But fortunately, it remains games correctly playables for our great pleasure!