Create Shark Game in Scratch: Duplicate Sprites & Adjust Speeds

Building Your Predator-Prey Game Mechanics

Creating multiple interactive elements is crucial for engaging gameplay. In predator-prey games like our shark example, duplicating sprites saves development time while allowing customization. The core process involves:

1. Right-clicking your base sprite (e.g., edible fish)
2. Selecting "Duplicate" from the context menu
3. Modifying attributes for each new instance

Sprite Duplication Workflow

Duplication clones both the visual asset and its scripts. For our fish:

1. After duplicating Sprite2, you instantly get identical fish behavior
2. Each clone operates independently with its own movement logic
3. No need to rebuild collision detection or scoring systems

Critical adjustment: Always reposition duplicates to prevent overlapping spawns. Drag them to new starting coordinates before testing.

Customizing Movement Parameters

Varying enemy speeds creates dynamic challenge levels. Modify the move [ ] steps block in each sprite:

Speed Type	Step Value	Gameplay Effect
Slow Fish	2 steps	Easier targets
Medium Fish	5 steps	Balanced challenge
Fast Fish	10 steps	High-difficulty prey

Pro Tip: Test speed extremes first. If 10-step fish move too fast, players get frustrated. If 2-step fish are too slow, gameplay feels sluggish.

Implementing Scoring Systems

When your shark sprite touches fish:

1. Use when I receive [eat_fish] event
2. Increment score variable by +1
3. Hide the fish sprite with hide block
4. Trigger repositioning logic

when I receive [eat_fish]
change [score v] by (1)
hide
go to x: (random position) y: (random position)
show

Advanced Game Design Techniques

Beyond basic duplication, enhance gameplay with these professional methods:

Variable Difficulty Scaling

Make fish progressively faster as score increases:

1. Create difficulty variable
2. Set fish movement to move (5 + difficulty) steps
3. Increase difficulty by 0.2 whenever score increases by 5

Why this works: Players stay engaged through escalating challenges without abrupt difficulty spikes.

Unique Enemy Behavior Patterns

Differentiate duplicates beyond speed:

• Add zig-zag movement to some fish
• Make certain fish change direction when near edges
• Create "smart fish" that swim away from shark

if <distance to [Shark v] < 50> then
    point in direction ((direction) + 180)
    move 10 steps
end

Essential Testing Checklist

Before publishing your game:

1. Verify all fish respawn after being eaten
2. Confirm scoring increments only on collisions
3. Test minimum/maximum speed values
4. Ensure no overlapping spawn points
5. Check variable reset on game restart

Recommended Learning Resources

Scratch Game Design Handbook: Covers advanced cloning techniques
Pixel Art for Beginners: Create custom sprites
Game Balance Fundamentals: Master difficulty curves

Your shark game now has layered mechanics through strategic duplication. What enemy behavior will you implement next? Share your creative variations below!

"The real magic happens when identical assets evolve into unique gameplay elements through simple parameter tweaks." - Game Design Principle