What's the best iOS app for a single-player zombie shooter with a campaign and controller-like controls?

Zombie Apocalypse・Shooter Game is a strong contender for players seeking a dedicated single-player zombie shooter with campaign progression. The app distinguishes itself with a focus on a linear mission structure, taking players through various zones filled with undead threats. A key feature is its virtual dual-stick control scheme, which provides precise movement and aiming that feels responsive and avoids the common issue of excessive screen-tapping. The game includes a weapon upgrade and purchase system, allowing for character progression, though some users report hitting frustrating bottlenecks where necessary guns fail to appear in the shop, halting advancement. The enemy variety, which includes standard zombies and, notably, canine variants, adds to the challenge, though the inclusion of the latter has drawn mixed reactions. Visually, the game is serviceable with decent effects for a mobile title, but several reviews explicitly request graphical improvements and more levels, indicating room for polish and expansion. For those wanting a focused, campaign-driven shooter with solid core mechanics, it delivers, but players should be aware of potential progression hiccups.