1

🎮

Top-Down Movement Done Right

Rigidbody movement with normalised input

Active

🎯

Goal for this step

Build smooth 8-way movement through the physics system.

1New 2D project. Player: sprite + Rigidbody2D (Gravity 0, Freeze Rotation Z!) + CapsuleCollider2D.
2Read input in Update, MOVE in FixedUpdate, input wants every frame, physics wants the physics tick. This split is Unity best practice.
3Set rb.linearVelocity from a normalised input vector ×- speed, normalisation kills the diagonal speed bug (an old friend by now).
4Walls: sprites with colliders. The physics engine handles all sliding-along-walls for free.

PlayerMove.cs

using UnityEngine;

public class PlayerMove : MonoBehaviour
{
    public float speed = 5f;
    Rigidbody2D rb;
    Vector2 input;

    void Awake() { rb = GetComponent<Rigidbody2D>(); }

    void Update()
    {
        input.x = Input.GetAxisRaw("Horizontal");
        input.y = Input.GetAxisRaw("Vertical");
        input = input.normalized;
    }

    void FixedUpdate()
    {
        rb.linearVelocity = input * speed;
    }
}

✏️

Fill in the Blanks

+15 XP

Input is read in Update but velocity is applied in , the physics tick. Diagonal speed is fixed by calling on the input vector.

🧠

Knowledge Check

+15 XP

Why freeze the Rigidbody’s Z rotation?

AZ does not exist in 2D

BCollisions would physically SPIN your character like a bumped shopping trolley

CIt saves memory

2

🎬

The Animator

Idle/walk animations driven by parameters

Locked

🎯

Goal for this step

Hook movement into Unity’s animation state machine.

1Grab free character sprites (kenney.nl, free game assets, no strings) and slice the sheet in the Sprite Editor.
2Select frames → drag onto the player → Unity creates an Animation + Animator. Make clips: Idle, WalkDown, WalkUp, WalkSide.
3The Animator window is a state machine, states and transition arrows (your RPG slime brain, visualised!).
4Add parameters Speed (float), DirX/DirY (float). Transitions test them: Speed > 0.1 → walk; direction picks which walk.
5Feed parameters from code: anim.SetFloat("Speed", input.magnitude). Flip side-walk with localScale.x = -1 instead of duplicate animations.

PlayerMove.cs (additions)

Animator anim;

void Update()
{
    // ... input reading ...
    anim.SetFloat("Speed", input.magnitude);
    if (input.x != 0 || input.y != 0)
    {
        anim.SetFloat("DirX", input.x);
        anim.SetFloat("DirY", input.y);
    }
}

✏️

Fill in the Blanks

+15 XP

The window is a visual state machine. Code drives it by setting like Speed, which transitions test against conditions.

🧠

Knowledge Check

+15 XP

The Animator IS a state machine. Where have you hand-built that exact pattern?

ANever

BThe GML slime (idle/chase/attack) and Pong’s MENU/PLAY/OVER, engines just draw the diagram for you

CIn CSS

3

⚔️

Sword Swings & Hitboxes

A short-lived trigger hitbox in facing direction

Locked

🎯

Goal for this step

Implement melee attacks with proper hitboxes.

1The sword hit = a child GameObject with a trigger BoxCollider2D, disabled by default, positioned by facing direction.
2On Space: enable it for 0.15 s via a coroutine, Unity’s "do this over time" tool (start, wait, finish, no manual timers!).
3yield return new WaitForSeconds(0.15f) pauses the coroutine, not the game.
4The hitbox’s OnTriggerEnter2D damages any Enemy component it touches (the GML obj_swing pattern, engine-grade).

SwordAttack.cs

using UnityEngine;
using System.Collections;

public class SwordAttack : MonoBehaviour
{
    public GameObject hitbox;

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
            StartCoroutine(Swing());
    }

    IEnumerator Swing()
    {
        hitbox.SetActive(true);
        yield return new WaitForSeconds(0.15f);
        hitbox.SetActive(false);
    }
}

⌨️

Code Challenge

+20 XP

Write the timed swing coroutine:

SwordAttack.cs

IEnumerator Swing()
{
    hitbox.SetActive();
    yield return new (0.15f);
    hitbox.SetActive();
}

💡 Hint: Turn the hitbox on, wait 0.15 seconds without blocking the game, turn it off.

🧠

Knowledge Check

+15 XP

Coroutines replace which manual pattern from your earlier games?

AThe draw call

BFrame-countdown timers (i-frames, serve delays, alarms), "wait then do" as readable code

CCollision checks

4

🧠

Enemy AI & Knockback

Chase-state slimes with physics knockback

Locked

🎯

Goal for this step

Build enemies that chase, hurt, and get knocked flying.

1Enemy prefab: sprite, Rigidbody2D (gravity 0), collider, Enemy.cs with hp and the idle/chase distances you know by heart.
2Chase: rb.linearVelocity = (player.position − transform.position).normalized × speed (in range), else zero.
3TakeDamage: hp down, plus knockback, rb.AddForce(direction * 8f, ForceMode2D.Impulse): real physics punch!
4Death at 0 hp: burst particles (Episode 3 prefab!), Destroy. Contact damage to the player comes next step.
5Prefab it, scatter five around the map.

Enemy.cs

using UnityEngine;

public class Enemy : MonoBehaviour
{
    public int hp = 3;
    public float speed = 2.2f, aggroRange = 4f;
    Transform player;
    Rigidbody2D rb;

    void Awake()
    {
        rb = GetComponent<Rigidbody2D>();
        player = GameObject.FindGameObjectWithTag("Player").transform;
    }

    void FixedUpdate()
    {
        float dist = Vector2.Distance(transform.position, player.position);
        if (dist < aggroRange)
            rb.linearVelocity = (player.position - transform.position)
                                .normalized * speed;
        else
            rb.linearVelocity = Vector2.zero;
    }

    public void TakeDamage(int amount, Vector2 fromDirection)
    {
        hp -= amount;
        rb.AddForce(fromDirection * 8f, ForceMode2D.Impulse);
        if (hp <= 0) Destroy(gameObject);
    }
}

✏️

Fill in the Blanks

+15 XP

A physics shove uses rb. with ForceMode2D.. The chase begins inside the distance.

🧠

Knowledge Check

+15 XP

Impulse knockback (vs teleporting the enemy back) feels better because…

AIt is one line

BPhysics integrates it: the enemy skids, recovers, collides believably, weight instead of teleport

CEnemies prefer it

5

❤️

Hearts, Damage & i-Frames

Player health with UI hearts and invincibility

Locked

🎯

Goal for this step

Complete the combat loop with player health done properly.

1PlayerHealth.cs: 6 half-hearts, an i-frames window after hits (a coroutine + sprite flashing, you know exactly why from GML).
2Enemy contact: OnCollisionStay2D (not Enter, standing IN an enemy must keep hurting… once per i-frame window).
3Hearts UI: Canvas with heart Images; update full/half/empty sprites from current hp (a loop over the array).
4Death: hp 0 → game-over panel + restart button (Episode 3’s scene reload).
5Pickups: heart drops (20% on enemy death, Instantiate a pickup prefab; its trigger heals and Destroys itself).

PlayerHealth.cs

public IEnumerator Hurt(int dmg, Vector2 knockDir)
{
    if (invincible) yield break;
    hp -= dmg;
    UpdateHeartsUI();
    if (hp <= 0) { GameOver(); yield break; }

    invincible = true;
    for (int i = 0; i < 6; i++)     // flash 6 times
    {
        sprite.enabled = !sprite.enabled;
        yield return new WaitForSeconds(0.12f);
    }
    sprite.enabled = true;
    invincible = false;
}

✏️

Fill in the Blanks

+15 XP

Continuous contact damage uses OnCollision2D rather than Enter. The flash-and-immunity window is handled by one guarded by an flag.

🧠

Knowledge Check

+15 XP

yield break inside a coroutine does what?

ACrashes it

BExits the coroutine early, like return, for the hurt-while-invincible and death cases

CPauses forever

6

🚪

World Flow & The Slice

Doors between scenes, spawn points, persistent health

Locked

🎯

Goal for this step

Connect scenes into a world and ship the vertical slice.

1Build 2 more scenes (forest, cave, File → New Scene, add to Build Profiles!).
2Door prefab: trigger + target scene name + spawn point id. Enter → LoadScene; a SpawnManager positions the player at the matching id on load.
3Persist health BETWEEN scenes: DontDestroyOnLoad on the player (and camera), Unity’s "persistent" flag.
4The slice checklist: move ✓ animate ✓ fight ✓ get hurt ✓ heal ✓ travel ✓. That set of verbs IS an action RPG.
5Episode 7 wraps it in real menus and UI. Save the project!

Door.cs

using UnityEngine;
using UnityEngine.SceneManagement;

public class Door : MonoBehaviour
{
    public string targetScene;
    public string spawnId;

    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.CompareTag("Player"))
        {
            SpawnManager.nextSpawnId = spawnId;
            SceneManager.LoadScene(targetScene);
        }
    }
}

⌨️

Code Challenge

+20 XP

Send the player through a door:

Door.cs

if (other.CompareTag())
{
    SpawnManager.nextSpawnId = ;
    SceneManager.(targetScene);
}

💡 Hint: Filter to the player tag, stash where they should appear, then load the destination scene.

🧠

Knowledge Check

+15 XP

DontDestroyOnLoad on the player solves which problem?

ASlow loading

BScene loads normally destroy everything, health/inventory would reset at every door without it

CEnemy respawns

Adventure Calls!Unity Action RPG

Adventure Calls!
Unity Action RPG