What's the best Android app for a fast-paced zombie shooter that's good for short gaming sessions?

Zombie Waves is a mobile action game from Fun Formula that caters to players looking for rapid, engaging zombie survival gameplay. The app stands out for its pick-up-and-play design, with levels and events structured to fit into brief downtime, such as during commutes or breaks. Key features include multiple game modes, regular special events, and a weapon upgrade system that adds depth through collectible and purchasable enhancements. For real-world use, it's well-suited for casual gamers who want a challenge without long commitments; users report that the difficulty scales reasonably until later stages, where weapon upgrades become more critical. However, reviews indicate a common caveat: progression can hinge on in-app purchases at higher levels, creating a pay-to-win dynamic for some. Additionally, while ads are integrated for rewards, they are generally considered non-intrusive, though occasional issues with ad loading on WiFi have been noted. Performance varies by device, with smoother experiences on newer models like the Galaxy S24 compared to older tablets. Despite these limitations, Zombie Waves maintains high ratings due to its addictive gameplay and consistent content updates.