Heart Diver is an arcade casual action mobile game. All you have to do in this game is to protect the heart of the princess from the attacking invaders which look like basic square boxes. You have to kill those invaders by holding and dragging over the boxes to link them up together and release the hold to kill them. The more you are able to kill with one single swoop, more the points you will be able to earn in this game. Other than that, there seem to be no other gaming contents. The storyline is pretty basic.
As the story goes, the main protagonist (the priestess) is supposed to stop the unstoppable blight from consuming the world. While she is unconscious, she will be fighting against the blight's mental barrage. And we need to help her fight off the invader. As the dialogue goes - "Come on, Priestess, Wake up!" You shake her gently, trying to rouse her from the deep sleep she's fallen into. "We don't have much time. The blight is coming, and we need you to fight it!". And this is basically the story intro of this game. We don't seem to have a good character voiceover to tell the story or to explain it to us. The game sort of feels like a experimental mini-project, with its basic gameplay features and lack of contents and very simple storyline.
Talking about the gameplay, all you have to do is to bind the invading squares together to destroy them. More you can link with single swoop, more the points you can score. The game do have some other rewards features but they don't seem to make much impact as there seems to be no good multiplayer gaming features available right now. And honestly, I don't think that there will be any in the near future.
In conclusion, heart diver is a pretty simple game with very simple basic gameplay where you have to try to get highest score possible. Basic gameplay, short written storyline, just a single background music and basic graphics tells that its most probably an experimental project game. Try out for some challenge as invading squares become more in number and faster as the level goes up.