Complex sentence: The game was free-to-play--it was free for users to play, though premium content could be earned or purchased, such as access to special items and blueprints, and more quests and features.
Split into simpler sentences: The game was free-to-play--it was free for users to play, with the additional option of earning or purchasing premium content. Premium content may include access to many special items and blueprints, and more quests and features.