If you've been a fan of Arcade games such as Raiden then you'll be an addict for Sky Force 2014, one of the best top-down Arcade space ship shooters. You control a ship and must upgrade it progressively while fighting the bad guys. It has a 3D view with depth-of-field that amazes in terms of graphic art and a beatifully matching sound track. Other features:
Sky Force 2014 has much more to offer, check the detailed review for a glimpse on what you're missing every minute when you're not installing it, especially since it's available for free on Google Play.