- Zombie Air Force upgrades: Over 180 upgrade options shape your aircraft, weapons, and defenses.
- Damage first: Boost primary and area damage early to clear waves faster.
- Survive next: Invest in aircraft durability once missions get longer and waves get heavier.
- Late game: Shift Credits toward defense performance and resource efficiency for repeat farming.
- Stay flexible: The game is in Alpha, so the upgrade tree can change between updates.
How the Zombie Air Force Upgrade System Works
Zombie Air Force is a co-op PvE air-combat shooter where you pilot aircraft against zombie hordes and giant Behemoths, using rockets, machine guns, airstrikes, and deployable defenses to push the frontline. With 180+ upgrades available, the system rewards players who plan a clear progression route instead of spreading Credits across every branch at once.
Upgrades in Zombie Air Force fall into six broad directions, each serving a different stage of the game:
| Upgrade Area | Priority | Best Stage | Main Benefit |
|---|---|---|---|
| Primary Damage | High | Early game | Stronger regular attacks shorten every battle |
| Area Damage | High | Early to mid game | One attack hits multiple zombies in dense waves |
| Survivability | High | Mid game | Prevents failed missions on longer runs |
| Defense Performance | Medium | Mid to late game | Better lane control and objective protection |
| Resource Efficiency | Medium | Late game | Faster farming and better reward value |
| Build Specialization | Situational | Late game | Commits to a specific aircraft, weapon, or role |
Concentrate Credits on one primary role first. A build with a fully upgraded main damage source consistently outperforms a build with every branch half-finished.
Upgrade Priority Path: Step by Step
Follow this sequence to turn early Credits into consistent mission clears. The order matters: each stage unlocks the ability to reliably farm the Credits needed for the next.
Maximize Primary Damage
Spend your first Credits on reliable single-target damage. Faster kills mean shorter battles and less pressure on your defensive positions, which directly improves your clear rate.
Expand Area Damage
Add multi-target coverage next. Wave-based missions become far more manageable when one rocket run or airstrike affects an entire cluster of zombies instead of scattered individuals.
Invest in Survivability
Longer missions and heavier waves punish pure offense builds. Improve aircraft durability and defensive resilience before attempting higher-difficulty content or extended survival runs.
Strengthen Defenses
Upgrade deployable defenses and lane control once enemies begin surviving multiple attack cycles. Position defenses near key approach routes and protect high-value objectives.
Optimize Resource Efficiency
With the combat core stable, shift toward farming speed and reward value. Efficiency upgrades deliver the strongest long-term returns and fund your final build specialization.
Do not invest heavily in resource-efficiency upgrades during the early game. They provide little immediate combat power and can slow your progression before your damage core is established.
Upgrade Builds by Playstyle
The best upgrade path depends on your goal. These four build archetypes cover the main ways to play Zombie Air Force, whether you fly solo or push the frontline with a squad.
Solo Progression Build
- Balanced damage and survivability
- Upgrade order: primary damage, area coverage, then durability
- Best for learning stages and flexible general play
- Con: requires more total upgrades than a specialized build
Fast Clear Build
- High-tempo crowd clearing
- Upgrade attack speed, area coverage, and mobility tools
- Best for rapid wave clears and short farming runs
- Con: weak against high-health targets without team support
Co-op Defense Build
- Sustained team protection
- Prioritize sustained damage over burst, then crowd control
- Best for defending fixed areas in longer multiplayer sessions
- Con: lower burst damage than an offensive loadout
Behemoth Damage Build
- Focused damage against giant threats
- Upgrade concentrated single-target damage and critical effects
- Best for boss encounters and high-difficulty survival
- Con: inefficient against large groups of standard zombies
Build Comparison Table
| Build | Damage | Survivability | Wave Clear | Best Mode |
|---|---|---|---|---|
| Solo Progression | ★★★★ | ★★★★ | ★★★☆ | Solo missions |
| Fast Clear | ★★★★ | ★★☆☆ | ★★★★★ | Farming runs |
| Co-op Defense | ★★★☆ | ★★★★★ | ★★★★ | Multiplayer |
| Behemoth Damage | ★★★★★ | ★★★☆ | ★★☆☆ | Boss fights |
In squad play, avoid duplicating roles. Pair a Fast Clear player with a Behemoth Damage player so crowd control and boss damage are both covered without wasted upgrades.
Credits: Funding Your Upgrades
Credits are the currency that drives every upgrade decision. The most efficient route is always the highest repeatable activity you can complete without frequent failures—a slightly easier stage cleared consistently outperforms a harder stage with repeated losses.
| Source | Efficiency | Recommended Method | Priority |
|---|---|---|---|
| Standard stage completion | Consistent | Repeat the highest stage you clear reliably | High |
| Wave and survival runs | Higher with defensive builds | Use sustained damage and crowd control | High |
| Co-op runs | High when coordinated | Assign roles: control, damage, defense | High |
| Repeatable bonuses | Varies by activity | Claim when it does not slow better runs | Medium |
| Upgrade spending | Highest when concentrated | Main damage source first, then coverage | High |
Upgrade the tool that defines your build before touching secondary options. Reaching a useful power breakpoint early makes every subsequent mission more profitable.
Upgrade Milestones to Hit First:
- Fully upgrade your primary damage source
- Unlock area damage for dense zombie waves
- Add survivability before high-difficulty missions
- Reinforce defenses on key approach lanes
- Invest in resource efficiency for long-term farming
Advanced Upgrade Tips
Small habits compound into faster progression. These tips apply regardless of which build archetype you choose.
- Keep an escape route open. Reposition before enemies close every path so you retain mobility when wave pressure spikes.
- Separate crowd damage from focused damage. In co-op, one player should handle groups while another burns down special enemies and Behemoths.
- Watch the wave before committing. Save powerful attacks and airstrike charges for special enemies or a Behemoth appearing mid-wave.
- Farm content you clear reliably. Consistency beats difficulty when measuring Credits per run.
- Match your build to the activity. Do not bring a Behemoth Damage setup to a wave-clearing mission, or vice versa.
Zombie Air Force is in Alpha, and the developer (fresh green beans) actively updates the game. Upgrade values and the tree structure can shift between patches—recheck your priorities after each major update.
Upgrade FAQ
Q: What are the best Zombie Air Force upgrades to buy first?
Start with primary damage, then area damage. Reliable offense shortens battles and reduces pressure on your defenses, which makes every later upgrade cheaper to reach through faster farming.
Q: How many upgrades are in Zombie Air Force?
The game advertises 180+ upgrades covering aircraft performance, weapons, airstrikes, and defensive structures. Because the game is in Alpha, the exact number and values may change with updates.
Q: When should I upgrade survivability?
Around mid game, once missions get longer and waves hit harder. Builds that invest only in offense tend to fail extended runs, so durability becomes essential before high-difficulty content.
Q: Should I focus on one upgrade branch or spread Credits out?
Focus on one primary role first. A concentrated build reaches useful power breakpoints faster, and you can add survivability and secondary tools afterward to cover its weaknesses.