The combat system in Kaizen handles automatic fighting, damage calculation, critical hits, and enemy progression through waves and stages.
Starting and stopping combat
Combat is controlled through the CombatService and operates on an automatic interval-based system.
startFighting() {
this.isFighting.set(true);
this.performAttack();
this.fightIntervalID = setTimeout(() => {
this.startFighting();
}, this.calculateAttackSpeed());
}
stopFighting() {
this.isFighting.set(false);
clearTimeout(this.fightIntervalID);
}
The combat system uses setTimeout for attack intervals, which recalculates the attack speed after each attack to account for upgrades and buffs.
Damage calculation
Damage is calculated using a multi-layered formula that combines base stats, modifiers, prestige bonuses, and upgrades.
The core damage calculation from CombatService.calculateDamage() (line 89):
let damage =
(character.baseStrength +
this.goldUpgradeService.getTotalEffect(UpgradeEffectType.FLAT_STAT_BOOST)) *
character.strengthModifier *
character.prestigeMultipliers.strength *
character.prestigeLevel;
Damage multipliers
After the base calculation, additional multipliers are applied:
const strengthBoost = this.prestigeUpgradeService.getTotalEffect(
UpgradeEffectType.FLAT_STAT_BOOST
);
damage *= 1 + strengthBoost;
const dpsPerCore = this.prestigeUpgradeService.getTotalEffect(
UpgradeEffectType.DYNAMIC_PER_CORE
);
const unusedCores = character.prestigeCores;
damage *= 1 + dpsPerCore * unusedCores;
Final damage is floored to the nearest integer: Math.floor(damage)
Critical hits
Critical hits can occur on any attack and multiply the final damage.
Critical chance
Base critical chance starts at 10% and can be increased through gold upgrades:
criticalHit() {
const criticalChance =
0.1 + this.goldUpgradeService.getTotalEffect(UpgradeEffectType.CRITICAL_CHANCE_BOOST);
return Math.random() < criticalChance;
}
Critical damage
When a critical hit occurs, damage is multiplied:
if (this.criticalHit()) {
attackAmount *=
2 + this.goldUpgradeService.getTotalEffect(UpgradeEffectType.CRITICAL_DAMAGE_BOOST);
}
Base critical damage is 2x (200%). The “Heavy Hitter” upgrade adds +5% per level, so at level 10 you’d have 2.5x critical damage.
Attack speed
Attack speed determines the interval between automatic attacks.
calculateAttackSpeed(): number {
const BASE_ATTACK_SPEED = 1000;
const SWIFT_ATTACK_SKILL_BOOST = 0.5;
const attackSpeedBoost = this.prestigeUpgradeService.getTotalEffect(
UpgradeEffectType.ATTACK_SPEED
);
const swiftAttackSkill = this.isSwiftAttacking() ? SWIFT_ATTACK_SKILL_BOOST : 1;
const finalAttackSpeed = Math.floor(
BASE_ATTACK_SPEED * (1 - attackSpeedBoost) * swiftAttackSkill
);
return finalAttackSpeed;
}
Base speed
With upgrades
Swift Attack skill
Base attack interval is 1000ms (1 attack per second).
The “Swift Strikes” prestige upgrade reduces attack interval by 5% per level. At level 10, attacks happen every 500ms (2 attacks per second).
When the Swift Attack skill is active, attack speed is multiplied by 0.5, effectively doubling attack speed for 5 seconds.SWIFT_ATTACK_DURATION = 5000; // 5 seconds
Enemy health scaling
Enemy health scales exponentially based on stage and wave progression.
From CombatService.calculateEnemyHP() (line 72):
const baseHP = 100;
const stageMultiplier = 1.5;
const waveMultiplier = 0.05;
const stagePower = Math.pow(stageMultiplier, character.currentStage - 1);
const wavePower = Math.pow(1 + waveMultiplier, character.currentWave - 1);
let enemyHP = Math.floor(baseHP * stagePower * wavePower);
Health reduction
Prestige upgrades can reduce enemy health:
const healthReduction = this.prestigeUpgradeService.getTotalEffect(
UpgradeEffectType.ENEMY_HEALTH_REDUCTION
);
enemyHP = Math.floor(enemyHP * (1 - healthReduction));
Enemy health scales extremely fast. Stage 20 enemies have ~33,000 HP, while stage 30 enemies have ~2.6 million HP before wave scaling!
Example calculations
| Stage | Wave 1 HP | Wave 10 HP |
|---|
| 1 | 100 | 155 |
| 10 | 3,834 | 5,952 |
| 20 | 33,262 | 51,625 |
| 30 | 2,618,431 | 4,065,228 |
Gold rewards
Gold is earned automatically when defeating enemies.
calculateGoldReward(): number {
const baseGold = 10 * this.characterService.character().currentStage;
const waveBonusGold = 1 + this.characterService.character().currentWave * 0.05;
let gold = baseGold * waveBonusGold;
// Critical chance for double gold
const critChance = 0.1;
if (Math.random() < critChance) {
gold *= 2;
}
return Math.floor(gold);
}
- Base gold =
10 × current stage
- Wave bonus =
+5% per wave (1.05 at wave 1, 1.50 at wave 10)
- 10% chance to double gold rewards (separate from combat critical hits)
Wave and stage progression
When an enemy is defeated, the player advances through waves and stages:
advanceWave() {
this.character.update((char) => ({
...char,
currentWave: char.currentWave < 10 ? char.currentWave + 1 : 1,
currentStage: char.currentWave === 10 ? char.currentStage + 1 : char.currentStage,
}));
}
Each stage contains 10 waves. Completing wave 10 advances to stage 2, wave 1.
performAttack() (line 52):
- Calculate base damage
- Check for critical hit and apply multiplier
- Subtract damage from enemy HP (floored)
- If enemy HP reaches 0:
- Award gold
- Advance wave/stage
- Calculate new enemy HP
performAttack() {
let attackAmount = this.calculateDamage();
if (this.criticalHit()) {
attackAmount *=
2 + this.goldUpgradeService.getTotalEffect(UpgradeEffectType.CRITICAL_DAMAGE_BOOST);
}
const remainingHP = Math.max(0, Math.floor(this.enemyHP() - attackAmount));
const defeated = remainingHP === 0;
this.enemyHP.set(remainingHP);
if (defeated) {
this.handleEnemyDefeat();
}
}