AirAttack HD vs Sky Force Anniversary
AirAttack HD
AirAttack HD is an award-winning vertically-scrolling, top-down arcade shoot-'em-up where you get to assume the role of an up-and-coming ace pilot. Featuring an intense, bullet-hell-like gameplay, you'll get to fight against a wide variety of enemies while piloting a nice selection of unique aircrafts which you upgrade and customize to your liking as well. The game is a mainly single-player game and as such, it offers plenty of exciting missions for you to embark on, each of which has 3 difficulty modes. Aside from campaign missions, there are even arcade and survival modes for you to truly put your skills to the test.What makes AirAttack such a popular game though is not only because of its real-time physics and destructible environments, but also because of its intuitive combat which is delivered through a whopping 7 control types - Touch, Relative, Tilt, Joypad, Mouse, Keyboard, and Gamepad. Having a World War theme helps a lot as well!
AirAttack HD is a somewhat older mobile game though and as such, its graphics might not be comparable to its latest sequel, AirAttack 2, but overall, the original AirAttack is still a very entertaining game to play and it manages to hold up to today's arcade standards.
Sky Force Anniversary
Sky Force Anniversary brings Sky Force to platforms other than Android and iOS, namely PC and consoles, allowing even more players to enjoy its exhilarating arcade shooting action. It is basically similar to Sky Force 2014 on mobile and features everything you'd expect to find in the latter, including challenging enemies and bosses, large number of missions, weekly PvP tourneys, an in-depth airplane upgrade system along with a wide variety of planes to fly as and weapons to blast enemies into smithereens. In this version, you can also play the game cooperatively with a friend through the game's local multiplayer option.Oddly enough, despite its similarities to Sky Force 2014, Sky Force Anniversary is available on Android as well. Unfortunately, I'm pretty sure the game doesn't support cross-platform cooperative gameplay so you can't exactly play with your friend cooperatively if he is on the PC and you on your phone.
Sky Force Anniversary is the best (and only) version of Sky Force that you can get for Nintendo Wii, PlayStation (3, 4 and Vita), and Xbox Live, but if you want to play the game on your mobile, you can get either the Anniversary version (Android only) or the 2014 version.