Deltazone is a tactical shooter set in a war-torn world where mysterious purple crystals called Veilstone have sparked a global conflict. Players lead a military squad through corrupted landscapes and abandoned cities, fighting against rival factions while dealing with the crystal's radiation effects that have mutated local wildlife and transformed the environment. The game combines strategic resource management of Veilstone crystals with squad-based combat, as players attempt to reclaim their homeland while navigating between hostile human forces and mutated creatures. The narrative unfolds across a campaign where control of these energy-rich crystals determines the balance of power in a world where alliances shift and survival depends on tactical decisions. Less