Metal Slug Defense

Metal Slug Defense is a strategy game with elements from tower defense games. It is a free-to-play title with microtransactions based on the Metal Slug side-scrolling shooter franchise. The regular band of heroes returns to prevent General Morden from once again executing a coup d'état. The game is played in a 2D environment where the player can manually scroll left or right. Each side has a base that needs to be protected. To win a stage the player must defend the base and send out soldiers and units to destroy the one on the other side. Near the top of the screen the HUD shows the health for both sides and a small map to keep track of units.

When a game starts AP (Action Points) are generated at a constant rate. When a certain amount has been reached, one or more units can be trained. They are sent out and move and attack on their own, to the right towards the base. Units include regular soldiers, engineers who set up barricades, robots, tanks etc. Units themselves have a bar that fills up and when they flash blue they can be clicked or tapped to execute a powerful attack. Instead of constantly sending out units it is possible to spend AP on the generation process itself, making it faster. Optional elements include freeing prisoners of war and collecting fuel until a powerful tank eventually becomes accessible to launch in difficult circumstances. By freeing all prisoners in a set of stages character abilities are unlocked.

Missions are presented on a world map with multiple stages each and daily challenges as well. By completing missions new units are unlocked and MSP is provided as the primary currency. Silver medals act as a premium currency. The currencies can be spent on customizing game elements and units with various upgrades, bonus items, acquiring new units, starting boosts, supplies, replaying failed games with a maximum power level and more. A deck is used to customized the unit order at the bottom of the screen. Levels can be replayed multiple times, but there are waiting times. Optionally various skin packs can be bought, including one based on the King of Fighters franchise. The game supports online multiplayer for up to four players, one-on-one or two-on-two.