It appears as though a new tower defense game has been thrown into the mix, and it offers up something that most others in the genre don't: two more sides. That is to say, it takes the concept of grid-based tower construction and bumps things up from 4 sided boxes to 6 sided cells. It's name is HexDefense and it's the new, Open-GL using kid on the block.
HexDefense adheres to the more "open" style of defense gameplay in which the towers themselves are used to block enemy movement. At least, some of the levels do. Others appear to be of the more traditional set-path variety. Regardless of the layout, players will have to protect their base from enemy waves for 35 levels. Earning funds to place and upgrade more towers, naturally.
Seeing as it's already in the App Store and is totally free, it's something for strategy aficionados to consider.