Balanced weapon progression is a cornerstone of engaging shoot 'em up (shmup) games, ensuring players feel both challenged and rewarded. Arcade game developers employ several key techniques to achieve this balance.

1. Tiered Weapon Systems: Developers often design weapons in tiers, starting with basic firearms and gradually introducing more powerful options. This progression keeps players motivated while preventing early-game overpowering.

2. Resource Management: Ammo or energy limits for high-powered weapons prevent spamming, encouraging strategic use. Players must weigh the benefits of powerful shots against limited resources.

3. Enemy Scaling: As players upgrade weapons, enemy difficulty scales accordingly. This ensures that stronger weapons don’t trivialize gameplay, maintaining a consistent challenge.

4. Trade-offs: Many games incorporate trade-offs, such as slower movement speed for heavier weapons or reduced firing rates for higher damage. This forces players to adapt their playstyle.

5. Playtesting & Iteration: Developers rely heavily on playtesting to fine-tune weapon balance. Feedback helps adjust damage outputs, firing rates, and availability to create a satisfying curve.

By combining these methods, arcade game developers craft shoot 'em ups that feel fair, dynamic, and endlessly replayable.