What's the best iOS app for a casual factory building game with idle elements?

Builderment is an iOS game that focuses on factory building and automation, where players start with basic resources and gradually expand their operations into complex production lines. The game stands out for its lack of forced advertisements, which many users appreciate as it allows uninterrupted gameplay, a rarity in free-to-play titles. Instead, players can opt to watch voluntary ads to earn gems, which range from 1 to 5 per view, and these can be used to purchase items like the gem tree—a structure costing 250 gems that provides a steady stream of gems over time. This system encourages either patience or spending, and some reviews indicate it can feel grindy for those aiming to unlock premium features without purchases. On the positive side, the game includes idle mechanics where resources generate even when the app is closed, perfect for casual players who prefer incremental progress. Features like intuitive building placement and resource chain management keep the experience engaging, with one user reporting playing for three hours straight due to its addictive loop. However, there are limitations: occasional bugs may require reinstalling the app, and some players have suggested adding automatic locking for buildings to prevent accidental moves. Overall, Builderment balances depth and accessibility, making it a strong choice for simulation enthusiasts who value ad-free core gameplay but are comfortable with optional monetization.