Arcade machines in run-and-gun games often feature dynamic weapon upgrades to enhance player engagement and gameplay depth. These upgrades are typically managed through in-game power-ups, score milestones, or hidden collectibles. When a player picks up a power-up, the machine’s hardware or emulated software alters the weapon’s attributes, such as fire rate, damage, or projectile type.

Classic arcade systems like those in "Contra" or "Metal Slug" use ROM-based logic to trigger upgrades, ensuring seamless transitions without lag. Modern emulators replicate this by simulating the original hardware behavior. Dynamic upgrades keep gameplay fresh, encouraging replayability and skill mastery.

The mechanics often include tiered systems—basic weapons evolve into advanced versions, sometimes with visual and auditory feedback to heighten immersion. This design not only rewards player skill but also maintains the fast-paced, adrenaline-fueled essence of run-and-gun arcade classics.