frogger-design

name	frogger-design
description	Game design reference for 3D Frogger arcade gameplay, mechanics, and progression
context	fork

Core Loop

Cross lanes of traffic and rivers to reach home.

One sentence. One mechanic (movement). One goal (reach the other side). Complexity comes from the environment, not the controls.

Controls

• Directional input: Move in 4 directions (up, down, left, right)
• Hop: Grid-based movement with smooth visual interpolation
• No attack, no items at launch — pure movement mastery

Game Structure

Zones (Top to Bottom)

1. Goal Zone (top): 5 home slots the frog must fill
2. River Zone: Logs, turtles, lily pads moving laterally — frog must ride them
3. Median: Safe strip between zones — breathing room
4. Road Zone: Cars, trucks, buses moving laterally — frog must avoid them
5. Start Zone (bottom): Safe spawn area

Lane System

• Each lane has ONE hazard type moving in ONE direction
• Adjacent lanes alternate direction (left, right, left, right)
• Speed varies per lane — outer lanes faster, inner lanes slower
• Gaps between hazards are ALWAYS passable (no impossible configurations)

Mechanics

Movement

• Grid-based: frog snaps to grid positions
• Visual interpolation: smooth hop animation between grid cells
• Hop arc: slight vertical arc for visual satisfaction
• Forward bias: moving forward is faster than retreating

Scoring

• Points per forward hop (10 pts)
• Bonus for consecutive forward hops without retreating (multiplier)
• Time bonus for reaching home quickly
• Extra life at score thresholds (10,000 pts)
• Filling all 5 home slots completes the level

Difficulty Progression

• Wave 1-3: Slow hazards, wide gaps, few lanes
• Wave 4-6: Medium speed, narrower gaps, more lane variety
• Wave 7-9: Fast hazards, tight gaps, all lane types active
• Wave 10+: Maximum speed, minimum gaps, hazard variety

Difficulty Curve Pattern

Tension ████████░░ (high traffic density)
Release ██░░░░░░░░ (median safe zone)
Tension ██████████ (river with tricky timing)
Triumph █░░░░░░░░░ (reaching home)

Enemy/Hazard Types

Road Hazards

Type	Speed	Width	Behavior
Car	Medium	1 lane	Steady speed, even spacing
Truck	Slow	2 lanes	Slow but long, blocks vision
Bus	Fast	2 lanes	Fast and long, scary
Motorcycle	Very Fast	1 lane	Unpredictable spacing

River Objects

Type	Speed	Width	Behavior
Log (small)	Slow	2 cells	Safe to ride
Log (large)	Medium	4 cells	Safe to ride, more room
Turtle group	Slow	3 cells	Submerges periodically!
Lily pad	Stationary	1 cell	Fixed safe spot

Death Conditions

• Hit by any road vehicle → squish (visual + audio)
• Fall in water (miss all platforms) → splash (visual + audio)
• Carried off screen edge by river object → splash
• Time runs out → fade out

Feel Parameters (Tunable via Blueprint)

HopDuration: 0.15s (time to complete one hop)
HopArcHeight: 30.0 units (vertical peak of hop arc)
InputBufferWindow: 0.1s (queue next input during hop)
InvincibilityFrames: 0.0s (none — arcade rules)
CameraFollowSpeed: 10.0 (smooth camera tracking)
RespawnDelay: 1.0s (pause after death before respawn)
TimePerLevel: 30.0s (countdown timer per attempt)