The Ultimate Guide to Creating a Tower Defense Game in Unity

Install Unity using Unity Hub, choose the 2022 LTS version, and create a new 3D core project named Udemy course tower defense to start your tower defense development.

Explore Unity's main windows—project, hierarchy, scene, game, and inspector—and learn to create scripts, add 3D objects, and inspect components like transform and collider.

Explore how Unity components shape objects with transform, mesh renderer, and colliders, add rigid bodies for physics, and customize behavior through scripts, while mastering navigation in 3D space.

Learn the basics of C# in Unity by building a simple custom component that manipulates a game object's transform and rigidbody using start and update.

Import prototype materials and build a testing ground with simple shapes, then assemble a tower and an enemy, using a parent body and a rotatable head for C sharp practice.

Create a Unity tower script that references the enemy transform and tower head, uses look at and distance checks, and visualizes attack range with gizmos.

Instantiate a bullet prefab at the tower head, then propel it toward the enemy by calculating the direction, normalizing it, and applying velocity to the bullet’s rigidbody.

Use Unity's OnTriggerEnter to damage enemies when bullets enter a trigger, destroy both the enemy and the bullet, tag enemies, and refactor with a create bullet method.

Learn how to implement automatic tower attacks with a cooldown in Unity by tracking time with Time.time, recording last attack time, and validating cooldown before attacking.

Learn how boolean return types and clean code improve attack logic in a Unity tower defense game, using early returns, null checks, and range validation.

Learn how to store multiple enemies in one variable using arrays and lists in Unity, access them by index, select a random target, and dynamically manage targets with a list.

Learn to use a for each loop to iterate through enemies in a list and find the closest to the tower by comparing distances within the attack range in Unity.

Use a for loop to spawn multiple enemies in Unity for a tower defense game, using an enemy creator, instantiating a prefab, randomizing positions, and tracking enemies in a list.

Learn how access modifiers differentiate public and private members, and implement encapsulation by using serialized private fields and a getter method to protect data while keeping it accessible.

Solidify your foundation in unity and scripting from the crash course and prepare for the main lessons to come. Look ahead to a new project in the next section.

Set up a Unity tower defense project, import the Tower Defense Pack, review enemy and tower assets, and test basic gameplay using Unity Hub and the Universal Render Pipeline.

Create a simple testing ground in Unity with a twisty road and surrounding fields to test enemy movement along the road and lay groundwork for a future tile-based level.

Learn to implement AI navigation in Unity with NavMesh, bake a road surface, and control enemies via NavMesh agents moving toward a waypoint.

Improve enemy movement by routing through the road center to avoid corners with a waypoint array and get next waypoint method, stopping at the end and adjusting speed and rotation.

Learn to smooth enemy rotation in Unity by facing the movement direction with horizontal rotation only, using direction to target, quaternion look rotation, and time.deltaTime for frame-rate independent turn speed.

Adjust the navigation system’s avoidance priority so faster enemies circle around slower ones instead of pushing them, using a simple line of code that maps urgent speed to avoidance priority.

Create a rotate object script to rotate wheel objects on the x-axis at a frame-rate independent speed, and test with two enemies using two-waypoint paths.

Learn to implement a death system for enemies in a Unity tower defense game using a castle trigger and destruction on entry; the next video covers respawn.

Implement a waypoint manager in Unity to fix enemy references to waypoints, build an enemy prefab, and load waypoints via a get waypoints method so new enemies receive the path.

Learn to build an enemy respawn system in Unity by setting up an enemy portal as the respawn point, using a prefab and an enemy manager with a cooldown timer.

Clean up the Unity tower defense project and prepare for tower testing by refining enemy management, navigation, and tower behavior, then wrap the project into an archive for download.

Set up a crossbow tower in Unity, organize scripts, and make the tower head rotate toward the enemy using rotation speed, quaternions, and smooth lerp.

Learn to detect enemies within a tower's attack range using a physics overlap sphere, draw gizmos, implement a random target within range, and handle null targets safely.

Explore inheritance, encapsulation, and polymorphism in Unity, illustrating how object oriented programming shares functionality across scripts and enables different towers to override common behavior.

Master inheritance in Unity by building a crossbow tower that inherits from a base tower, sets protected fields, and implements a canAttack workflow for future overrides.

Implement raycast detection to find enemies from the crossbow’s gun point, compute a normalized direction to the target, and trigger an attack with recoil visuals.

Create tower attack visuals by using a line renderer with an emission blue laser, control laser duration with a coroutine, and disable rotation to sync visuals with the attack.

Learn to create a glow effect for a crossbow tower in Unity using a coroutine loop that lerps emission intensity over cooldown, with material instancing and a mesh renderer.

Learn to make a cross bolt tower glow by dynamically changing its emission color with intensity using color lerp and a coroutine, with start color, end color, and gamma-space correction.

Learn to create dynamic laser strings for a crossbow in Unity by using line renderers with front and back start/end points, synced to a moving rotor.

Move a rotor along the z axis between loaded and unloaded positions in Unity, using a coroutine and lerp over a duration, with line renderer glow updates.

Advance the core game loop by implementing a damage system and level creation, enabling a first playable level while preparing a priority target system for towers like the crossbow.

Implement a damage system using an IDamageable interface to let towers damage enemies, with take damage logic, health checks, and raycast-based detection for targeting.

Prioritize enemies by the least remaining distance to the finish line, computing total distance along waypoints and updating remaining distance to guide tower targeting.

Learn to select the most advanced enemy by remaining distance to the finish line within a tower's attack range, using enemy components to compare distances.

Learn to center a tower’s targeting by adding an enemy center point in Unity, using an enemy component, center point transform, and update‑driven visuals for precise, responsive attacks.

Define enemy type with enum, create priority targets and possible targets lists, and ensure priority targets are targeted first, with fallback to possible targets.

This lecture demonstrates building an optional dynamic target change system for towers, using a target check interval to periodically reselect enemies within range and swap targets as they advance.

Fix tower shooting through obstacles by refining raycast hit detection and enemy targeting, and switch to mesh colliders for precise collision in Unity.

discover a tile-based level creation system that speeds up level design by swapping tile meshes and materials through a tile slot, enabling corners, bridges, and enemy routes.

Create and configure tile assets for a Unity tower defense game by building a level scene, road and field tiles, and prefabs with mesh colliders for future navmesh use.

Create a Unity custom editor button to toggle a tile slot property and wire it to the tile slot script, supporting multi-object editing with targets and serialized object update.

Update tile visuals using a grid builder and tile set holder to switch meshes and materials from reference tiles, including road, field, and sideway. Learn editor setup and slot logic.

Rename tiles and update their colliders in Unity by switching between box and mesh colliders, adding inner and outer corner references, and syncing collider properties across parent and child objects.

Create and organize tile presets with headers, labels, and buttons in the Unity editor; manage hills, bridges, corners, and road while rotating and adjusting tile positions for efficient level layout.

Create a Unity grid builder that instantiates a tile prefab to form a 2d xz grid, controlled by grid length and width.

Fix missing tiles by building a five-by-five grid, add inner and outer corner small tiles, and update the grid builder prefab and tile set for Unity tower defense.

Learn how to fix bridge tiles in Unity by adjusting y-levels, refining prefabs, and resetting colliders to align bridges with hills, fields, roads, and sideway.

Enable automatic navmesh updates by updating tile layers for road tiles, calling update navmesh after changes, and rebuilding the grid to ensure physics collider geometry is used.

Upgrade the waypoint system and wave management to create different paths for waves of enemies, implement clean-up steps, and refine prefab handling for a reusable tower defense project.

Build a scalable level with two enemy paths and multiple waypoint sets, and implement an enemy manager that spawns from different portals while testing slopes.

Refactor the enemy system to distribute waves across multiple portals, implement an enemy portal, and enable portals to spawn enemies from their own locations.

Improve the waypoint system by giving each portal a dedicated waypoint set and collecting those waypoints from portal children into the enemy portal’s list via a setup method.

Improve waypoint navigation for enemies by dynamically selecting the next waypoint based on distance, refactoring waypoint management, and ensuring smooth pathing in a Unity tower defense game.

Create and manage multiple enemy waves in Unity by converting wave details to an array of level waves, tracking with a wave index, and triggering next waves with bounds checks.

Implement wave timers by tracking active enemies in a portal list, removing defeated units as they die or reach castle. Manage wave completed, time between waves, and force next wave.

Implement dynamic level changes in a tower defense game using Unity: introduce new paths after waves, update portals and waypoints, and refresh the navmesh to adapt enemy routes.

Discover how to align enemy visuals to slope surfaces in Unity by raycasting for the ground normal and smoothly rotating visuals via quaternion slerp.

Archive the project and attach it to the video. Download it for verification, and thank you—see you in the next video.

Create a custom Unity camera controller using the old input system to pan, rotate, and fly around a field with smooth damped movement, plane-constrained forward, and keyboard or mouse input.

Master camera rotation in Unity by rotating around a focus point with mouse input, using a rotation speed and vertical pitch clamp, plus raycast-driven focus point alignment.

Implement a camera zoom in Unity using the mouse scroll wheel, with serialized fields for zoom speed and min and max zoom, and smooth damp to clamp the camera's y-position.

Move the camera by holding the middle mouse button, computing the mouse delta for horizontal and forward movement, ignoring vertical, and smoothly translating toward a damped target position.

Implement edge-based camera movement in Unity by moving the camera when the mouse touches screen edges, using an edge threshold and smooth damping with delta time.

Set camera boundaries by anchoring to the level center and clamping target position within a maximum distance, using center-to-target direction and vector normalization for keyboard, mouse, and edge movement.

Master smooth camera transitions in Unity by fixing the startup snap, switching between menu and game views with a coroutine, and aligning pitch with x-rotation for seamless control.

Learn to create a camera shake in Unity using a coroutine, with duration and magnitude controls, original position reset, and per-frame random offsets.

Organize the project by cleaning up and fixing bugs, creating a camera scripts folder, moving relevant scripts into it, then archive the project for download and comparison.

Create an in-game ui with hp, timers, and main menu. Import fonts, borders, icons, and textures; enable Text Mesh Pro and 2D sprite package in Unity.

Lay out the menu in Unity with a canvas and scalable screen. Add play, settings, and quit buttons with TextMesh Pro and sliced borders for level selection.

Arrange main menu buttons using a grid layout group and a button holder, control button sizes and spacing, and organize the hierarchy with a background image and title.

Learn to switch between menus in Unity using a UI manager that toggles visibility for main menu, settings, credits, and level selection, with back and quit functionality.

Set up a credits UI in Unity and add a hyperlink button to promote links like a YouTube channel or website, using a simple script to open the URL.

Design a settings UI in Unity with sliders to tune camera sensitivity and volume for SFX and music, using a grid layout and custom slider visuals with an audio manager.

Create settings UI logic in Unity to control camera sensitivity with keyboard and mouse sliders, use lerp for smoothing, and persist values with PlayerPrefs.

Implement settings UI logic for mouse and keyboard sensitivity in Unity, using sliders and TextMeshPro text displays to show percentages, with load/save via PlayerPrefs and initial awake initialization.

Create an in-game health points (thread) display, wire it to a game manager that tracks max hp and current hp, and update the UI as enemies enter the castle.

implement a currency system in unity by updating a game manager currency variable when enemies die, and display resources via an in-game currency ui.

Build in-game ui buttons for a tower defense game using a grid layout group, content size fitter, and sprite editor icons, with text mesh pro labels and bordered backgrounds.

Animate ui elements with a reusable ui animator that moves rect transform via a coroutine using anchored position, offset, and duration; toggle wave timer and build buttons with keyboard input.

Learn to animate UI buttons with a hover scale effect using a UI animator and coroutines, applying a single scalable coroutine per button and handling pointer enter/exit events.

Learn to implement a fade in and fade out effect in Unity by animating a full-screen UI image with a color lerp over a duration using a coroutine.

Pause UI in Unity showcases an in‑game pause menu with resume, settings, and main menu, controlled by escape and time scale, plus pose UI and pose settings UI.

Clean up the Unity tower defense UI by renaming settings UI and main menu UI, keeping a functional project ready for archiving and reuse.

Develop a build manager for tower placement and level transitions with fade effects and in-world level buttons. Prototype tile-based tower building with hover indicators and tile movement via a coroutine.

Learn to build a Unity tower defense build system by creating build slots on tiles, managing selection with a build manager, and moving tiles on hover.

Create a centralized Unity build system by wiring UI build buttons to the build manager, enabling the build menu on tile selection and spawning a tower atop the tile.

Learn to build towers in Unity using a UI build button linked to a build manager, spawning towers at a selected slot, with currency costs and UI updates.

Block tower placements with a build slot boolean that becomes false after building, preventing duplicates and road interference; update build manager and grid logic to mark tiles unavailable.

Learn how to implement a tower unlocks system in Unity, using a level manager and data-driven tower unlocks to control which towers appear per level and update UI buttons.

Create a reusable UI feedback system in Unity that shakes UI elements on failed builds or castle breaches. Leverage UI animator and configurable shake magnitude, duration, and optional rotation.

Display a tower's attack radius using a line renderer to draw a circular radius around the tower, using 50 segments to visualize range in Unity.

Build a tower preview system in unity by converting a tower to a non-attacking preview, showing an attack radius, and enabling tile-based tower placement with preview visuals.

Create and manage a tower preview system in Unity, showing previews on hover or select, updating unlocked buttons, and canceling previews via the build manager.

Learn to implement build-system hotkeys in Unity by reading keyboard input, mapping number keys to unlocked build buttons, and confirming builds with space.

Fix null reference errors and UI conflicts in the tower defense build flow by guarding builds when the mouse is over UI and enabling hotkeys only when active.

Finish the project by implementing the game loop and scene management, enabling play, level selection, level progression, and the main menu, plus adding the audio system and tower/enemy setups.