This guide avoids mission-specific spoilers. It discusses enemy abilities, tower roles, campaign progression, and achievement requirements in general terms.
Fast answer
The answer before the background
For a reliable opening, pause or slow the action, inspect the route, and place a small group of affordable damage towers where aliens will pass more than once. Add a second damage type when shielded or fast enemies appear, then upgrade the towers covering the longest section of the route before spreading into new build sites. Keep resources in reserve for the next wave, use special weapons on dangerous clusters rather than routine targets, and sell or reposition towers only when the new path clearly improves coverage. Finish the story campaign before focusing on challenge medals or achievement cleanup.
Start here
A direct opening plan for your first missions
The safest beginner approach is to make the route do part of the work. Before building, turn on the path indicators and identify where aliens can be made to pass the same firing arcs repeatedly. On open maps, a tower’s force field can lengthen the route, so a carefully placed tower may be valuable even when its direct damage is modest. The official manual confirms that longer routes give towers more time to fire and can send enemies past the same defenses multiple times.
Build only enough to handle the first wave, then watch what actually threatens the cores. Avoid filling every available slot immediately. Your early resources are more useful when reserved for an upgrade or a counter to the next enemy type. A practical sequence is: establish one damage cluster, upgrade its best-covered tower, add coverage for a second route, and keep a reserve for emergencies.
Use the build menu’s range preview before confirming a tower. A tower that reaches two bends or a return path is usually a better investment than one that covers a short, isolated stretch. If a tower covers only the entrance, ask whether it will still matter during the final wave; if not, place it farther along the route or plan to sell it later.
- Read the upcoming enemy icons before committing to upgrades.
- Favor overlapping coverage at bends, chokepoints, and repeated passes.
- Upgrade a useful existing tower before building several weak replacements.
- Use speed-up during safe waves, but return to normal speed when a new enemy type arrives.
| Situation | Beginner response | Reason |
|---|---|---|
| Fast enemies | Use sustained fire and fire effects where available. | The manual notes that fast enemies are especially vulnerable to laser and fire damage. |
| Shielded enemies | Include projectile damage before relying on beam damage. | Projectile attacks help remove shields so other weapons can become effective. |
| Stealth enemies | Use detection support and inspect the route carefully. | Long-range towers may not see stealth units reliably without disruption. |
| Regenerating enemies | Maintain continuous damage instead of brief bursts. | Regeneration can occur when the enemy is not receiving damage. |
The enemy interactions above come from the official manual. The build order is a recommendation, not a mandatory solution; maps are intentionally open-ended and can support several successful defenses.
Core strategy
How to place, upgrade, and sell towers
Think in terms of coverage per resource rather than tower count. A level-one tower in a strong location can outperform a higher-level tower that sees only one short section of road. Once a tower is firing throughout most waves, upgrade it before adding another tower of the same role. Higher upgrade levels are much more expensive, so do not spend your entire bank on a single red-level tower if the next wave introduces a counter you cannot answer.
Layer different functions. Damage towers handle ordinary targets, while slowing, burning, shield disruption, stealth disruption, and boosting effects make the whole group more effective. The manual lists enemy effects such as regeneration, speed, shielding, and stealth, along with tower effects that can counter them. You do not need every tower type in every mission, but you should avoid a defense that depends on one damage behavior.
Selling is not a failure. It returns part of the construction cost and can change the enemy route or free a slot for a better tower. Sell when a tower has lost relevance, when a path change creates more repeated coverage, or when a new enemy type exposes a clear weakness. Do not sell reactively while a core is already under attack; make the change between waves or from a checkpoint.
Special weapons are best saved for moments that would otherwise force expensive rebuilding. Use them on dense groups, dangerous bosses, or a wave that combines several problems. Command team choices and tower items alter the available tools, so read their descriptions rather than assuming one loadout is universally strongest.
- Place support towers where several damage towers can benefit from them.
- Use the alien inspection window when an enemy survives unexpectedly.
- Keep at least one emergency option: spare resources, a special weapon, or a checkpoint.
- When chasing medals, remember that resource savings and surviving cores both influence results.
| Priority | What to improve first | Why it matters |
|---|---|---|
| 1 | Coverage of the main route | A defense that cannot see the route cannot benefit from later upgrades. |
| 2 | The strongest repeated firing position | Repeated exposure increases the value of every shot. |
| 3 | A missing counter | A small amount of utility can prevent a complete defensive collapse. |
| 4 | Extra damage and high-level upgrades | These are most useful after the route and enemy responses are stable. |
The official manual says score is affected by kills, cores currently housed, resources held, tower investment, and floating cores. For a first clear, prioritize survival. For gold medals, replay the mission after you understand its waves and optimize spending.
Progression
A practical campaign and achievement path
Play the story campaign in order and treat the first clear of each mission as reconnaissance. The game records checkpoints when waves enter, and the manual says you can resume from the latest checkpoint or return to an earlier one after a defeat. Use this system to test a response without restarting the entire mission, especially when learning when a boss or special enemy arrives.
After clearing a mission, replay it only if you have a specific goal: improve the medal, preserve more cores, finish without selling, or learn a restricted tower mode. Do not grind every gold medal immediately. New tower items, command team options, and enemy combinations make later missions a better training ground for advanced play.
For an achievement or trophy route, allow normal play to unlock the basic milestones first. Early examples include earning a bronze medal, upgrading a tower, building a large number of towers, selling towers, inspecting enemies, and using special weapons. The achievement list also includes campaign completion, medal collection, tower-specific construction totals, challenge-mode endurance, and cooperative objectives. Several of these are naturally cumulative, so forcing them too early can make a mission harder than necessary.
Once the main story is comfortable, move to challenge modes. These can alter tower limits, alien behavior, resources, core rules, or pathing. Read the challenge description and change your plan accordingly; a strategy that works in Story mode may be invalid when upgrades or tower types are restricted. If you own Aftermath, approach its larger open-ended missions as advanced practice rather than as an introduction.
- First clear: survive and learn the wave order.
- Second clear: improve the medal or reduce wasted spending.
- Third clear: target a specific achievement, challenge rule, or tower restriction.
- Leave multiplayer achievements and high-score attempts until you understand the core systems.
| Stage | Goal | Common mistake to avoid |
|---|---|---|
| Early campaign | Learn route manipulation and enemy counters. | Copying one tower type everywhere. |
| Mid campaign | Use support effects and deliberate upgrades. | Spending all resources before the final waves. |
| Challenge modes | Adapt to the altered rule set. | Assuming Story-mode economy still applies. |
| Achievement cleanup | Combine compatible objectives in planned runs. | Restarting randomly without a clear objective. |
The current Steam achievement page lists 65 achievements, including campaign, medal, tower, challenge, and co-op objectives. Console achievement or trophy totals and downloadable-content availability may differ, so check the platform-specific list before planning a completion run.
Avoid these errors
Common beginner mistakes and their fixes
The most damaging mistake is building for the route you see now instead of the route you can create. A tower may redirect aliens, and that redirection can either improve or ruin your coverage. Always check the updated path after placing or selling near an intersection.
Another common error is upgrading blindly. A high-level tower is not automatically the best purchase if it covers a poor angle, cannot detect the next enemy, or duplicates a role already represented elsewhere. Inspect survivors and use the information window to identify shields, stealth, regeneration, or speed effects.
Beginners also tend to spend every resource as soon as it arrives. The scoring system rewards resource reserves, and more importantly, unspent resources let you answer surprises. Keep a buffer until you know the next wave is harmless. Finally, do not confuse losing a core with losing the mission. If the map still allows recovery, stabilize the route and use the next wave to rebuild instead of abandoning the run.
- Do not place towers merely because a build slot is empty.
- Do not let one damage type become your entire defense.
- Do not chase gold before you can clear the mission consistently.
- Do not ignore the path preview after changing a tower layout.
- Do not waste a special weapon on a wave that ordinary towers already control.
FAQ
Common questions
What should I build first in a new mission?
Build a compact damage cluster covering a bend or repeated section of the route. Add only enough early coverage to survive the first wave, then upgrade the tower with the best sustained firing position and reserve resources for the next enemy type.
Should I upgrade towers or build more towers?
Upgrade when an existing tower has strong coverage and will keep firing for most of the mission. Build another tower when coverage is missing, a new enemy counter is required, or the current tower cannot reach an important route.
How do I deal with shielded, stealth, and regenerating enemies?
Use projectile damage to help remove shields, detection or disruption support for stealth, and continuous damage against regeneration. These interactions are described in the official manual, but the exact best placement depends on the map.
Is selling towers worth it?
Yes. Selling returns part of the cost and can improve the path or replace an obsolete role. Sell deliberately between waves rather than during an emergency unless the sale immediately prevents a core loss.
When should I start achievement or trophy hunting?
Start after your first campaign clears. Many construction, kill, upgrade, and basic medal objectives happen naturally. Then replay selected missions for no-sale, high-medal, restricted-tower, challenge, and cooperative objectives.
Sources
What we checked
Official listings establish current availability and product facts. Community pages are used for mechanics and build history, then labeled separately.