Touch Arcade writes:
"In November, we profiled a $0.99 game called Blue Defense! [App Store] which we praised as a "simple but effective shooter." Developer John Kooistra managed to blend together a simple concept into a really solid shooter and won us over along with many of our readers.
His followup title is appropriately enough called Blue Attack! [App Store, $1.99] in which you take the offense and track down the Red invaders from the original game. Kooistra has added a significant degree of complexity to the game by offering upgradable ships with improved weapons and capabilities. Yet he still manages to offer a surprisingly fun and deep game."