In battle, both GDI and Nod players can also choose from Offense, Defense, and Support classes, further compounding the customization options.
Points may be spent to unlock new units, facilities, and abilities, allowing for the development of a powerful, customized military force over the course of the game. Tiberian Twilight allows players to develop a persistent persona throughout the campaign, awarding experience points for each unit destroyed, from one scenario to the next. The introduction of enormous Crawler units, which function as mobile bases of operations and production, keeps the action moving around the map and adds new strategic considerations. The fourth full release in the original C&C line plays similarly to the more recent games in the real-time strategy series, with fast action, smooth 3D graphics, and sophisticated tactical attacks and counter-attacks between balanced but different forces. The cold-steel justice of the Global Defense Initiative and the mystic influence of Kane's Brotherhood of Nod clash for the final time in Command & Conquer 4: Tiberian Twilight.