Metal Slug Defense (メタルスラッグディフェンス) is a tower defense game developed by SNK Playmore for iOS and Android mobile devices. It was later ported to Steam.
A sequel to this game, titled Metal Slug Attack, was released on February 2016.
Metal Slug Defense is a tower defense game that features a wide variety of Units which can be deployed on the battlefield. The main goal of the game is to destroy the enemy's base before they could destroy the player's.
Rumi Aikawa can be seen on the bottom left providing AP or Action Points, tapping her when an enough of AP has been accumulated will upgrade the player's base level to the next level, gradually increasing the AP regeneration on each base levels. When the sufficient time is up, a "Metal Slug Attack" power-up can be deployed where a Super Vehicle-001 will charge in the battlefield, either instantly killing most infantry units or dealing heavy damage against vehicles.
The main feature of the Metal Slug Defense are the units. You can upgrade them with MSP in order to bolster their base stats such as HP, attack damage, and speed. Most units can be bought in the game's dedicated shop while some can be unlocked via Events or Log-in campaigns.
In the single player mode of the game, you may also purchase for power-ups while in battle, such as a Super Metal Slug Attack where a Super Vehicle-001 Type-R will charge against the enemies or a Fever Time in which your base AP level will temporarily be set to the max while the production gauge won't work, thus allowing any units to deployed many times until the unit cap has been reached.
Multiplayer modes such as Co-Op or Wi-Fi Versus can be played, remember to have a strong internet connection while playing against other players.