What's the psychological concept behind mobile game design and marketing? I see a very common trend in how every mobile game is being designed and advertised on the market. 

The common features are (not limited to):


Very cartoony graphics (big heads small bodies)
Characters standing on the side of every presentation screenshot
Overblown attitude of characters, characters show very exaggerated  facial expressions whether it be angry or classy.
Very simplistic captions and feature descriptions like "choose your weapon",  "kill your enemy", "build your empire"
Flashy graphics with colourful and glowing stuff, often exaggerated to the levels that its visually overwhelming


I am currently clueless how such marketing and design appeal to anyone? Is it aimed at children (by eventually making their parents pay for in game purchases)? Personally for me its quite repulsive, but since every other game is following it they must be doing something right?
Old question, but still relevant. I think that the success of these kind of simple (and stupid?) games have several explanations but the game makers are less interested in why simple and stupid games are very financially successful and instead they just follow the trend.
It is not only games but also many other products and marketing which are created in this way: Simple and often stupid. Simplicity has advantages because the customer and consumer has limited time and limited energy to learn the new thing, and if it were a complicated advanced computer game where you have to fly around in deep space for a week before anything ever happens, then your brain would not receive a reward and you would get bored (like I got). On the contrary if the game quickly rewards you and is simple to learn then it becomes more addictive.
The cuteness of game characters has been around for long and in Japan many products are created and marketed with cuteness which has been successful now also in the Western world.
There was a major hit game called Candy Crush saga which is very simple, tries to look cute and it rewards the player almost directly just when you get three in a row...That way it will be tempting for the consumer to continue because you got rewarded. Compared to more complicated games which are more difficult to learn.