fix: game balance — gold scaling, solo DEF, floor-scaled items, healer targeting, AI fallback

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

combat/combat.go

@@ -97,14 +97,17 @@ func MonsterAI(m *entity.Monster, players []*entity.Player, turnNumber int) (tar
 	}
 	if rand.Float64() < 0.3 {
 		minHP := int(^uint(0) >> 1)
-		minIdx := 0
+		minIdx := -1
 		for i, p := range players {
 			if !p.IsDead() && p.HP < minHP {
 				minHP = p.HP
 				minIdx = i
 			}
 		}
-		return minIdx, false
+		if minIdx >= 0 {
+			return minIdx, false
+		}
+		// Fall through to default targeting if no alive player found
 	}
 	for i, p := range players {
 		if !p.IsDead() {

game/event.go

@@ -88,6 +88,7 @@ func (s *GameSession) spawnMonsters() {
 				m.HP = 1
 			}
 			m.MaxHP = m.HP
+			m.DEF = m.DEF / 2
 		}
 		s.state.Monsters[i] = m
 	}
@@ -111,21 +112,25 @@ func (s *GameSession) spawnBoss() {
 	if s.state.SoloMode {
 		boss.HP = boss.HP / 2
 		boss.MaxHP = boss.HP
+		boss.DEF = boss.DEF / 2
 	}
 	s.state.Monsters = []*entity.Monster{boss}
 }
 
 func (s *GameSession) grantTreasure() {
+	floor := s.state.FloorNum
 	for _, p := range s.state.Players {
 		if rand.Float64() < 0.5 {
+			bonus := 3 + rand.Intn(6) + floor/3
 			item := entity.Item{
-				Name: "Iron Sword", Type: entity.ItemWeapon, Bonus: 3 + rand.Intn(6),
+				Name: weaponName(floor), Type: entity.ItemWeapon, Bonus: bonus,
 			}
 			p.Inventory = append(p.Inventory, item)
 			s.addLog(fmt.Sprintf("%s found %s (ATK+%d)", p.Name, item.Name, item.Bonus))
 		} else {
+			bonus := 2 + rand.Intn(4) + floor/4
 			item := entity.Item{
-				Name: "Iron Shield", Type: entity.ItemArmor, Bonus: 2 + rand.Intn(4),
+				Name: armorName(floor), Type: entity.ItemArmor, Bonus: bonus,
 			}
 			p.Inventory = append(p.Inventory, item)
 			s.addLog(fmt.Sprintf("%s found %s (DEF+%d)", p.Name, item.Name, item.Bonus))
@@ -134,10 +139,48 @@ func (s *GameSession) grantTreasure() {
 }
 
 func (s *GameSession) generateShopItems() {
+	floor := s.state.FloorNum
+	// Weapon bonus scales: base 3-8 + floor/3
+	weaponBonus := 3 + rand.Intn(6) + floor/3
+	// Armor bonus scales: base 2-5 + floor/4
+	armorBonus := 2 + rand.Intn(4) + floor/4
+	// Prices scale with power
+	weaponPrice := 40 + weaponBonus*5
+	armorPrice := 30 + armorBonus*5
+	// Potion heals more on higher floors
+	potionHeal := 30 + floor
+	potionPrice := 20 + floor/2
+
 	s.state.ShopItems = []entity.Item{
-		{Name: "HP Potion", Type: entity.ItemConsumable, Bonus: 30, Price: 20},
-		{Name: "Iron Sword", Type: entity.ItemWeapon, Bonus: 3 + rand.Intn(6), Price: 40 + rand.Intn(41)},
-		{Name: "Iron Shield", Type: entity.ItemArmor, Bonus: 2 + rand.Intn(4), Price: 30 + rand.Intn(31)},
+		{Name: "HP Potion", Type: entity.ItemConsumable, Bonus: potionHeal, Price: potionPrice},
+		{Name: weaponName(floor), Type: entity.ItemWeapon, Bonus: weaponBonus, Price: weaponPrice},
+		{Name: armorName(floor), Type: entity.ItemArmor, Bonus: armorBonus, Price: armorPrice},
+	}
+}
+
+func weaponName(floor int) string {
+	switch {
+	case floor >= 15:
+		return "Mythril Blade"
+	case floor >= 10:
+		return "Steel Sword"
+	case floor >= 5:
+		return "Bronze Sword"
+	default:
+		return "Iron Sword"
+	}
+}
+
+func armorName(floor int) string {
+	switch {
+	case floor >= 15:
+		return "Mythril Shield"
+	case floor >= 10:
+		return "Steel Shield"
+	case floor >= 5:
+		return "Bronze Shield"
+	default:
+		return "Iron Shield"
 	}
 }
 

game/turn.go

@@ -117,9 +117,19 @@ func (s *GameSession) resolvePlayerActions() {
 			case entity.ClassHealer:
 				targetIdx := action.TargetIdx
 				if targetIdx < 0 || targetIdx >= len(s.state.Players) {
-					targetIdx = 0 // heal self by default
+					targetIdx = 0
 				}
 				target := s.state.Players[targetIdx]
+				if target.IsDead() {
+					// Find first alive player to heal instead
+					for j, candidate := range s.state.Players {
+						if !candidate.IsOut() {
+							target = candidate
+							targetIdx = j
+							break
+						}
+					}
+				}
 				before := target.HP
 				target.Heal(30)
 				s.addLog(fmt.Sprintf("%s healed %s for %d HP", p.Name, target.Name, target.HP-before))
@@ -203,10 +213,7 @@ func (s *GameSession) resolvePlayerActions() {
 	// Award gold only for monsters that JUST died this turn
 	for i, m := range s.state.Monsters {
 		if m.IsDead() && aliveBeforeTurn[i] {
-			goldReward := 5 + s.state.FloorNum
-			if goldReward > 15 {
-				goldReward = 15
-			}
+			goldReward := 5 + s.state.FloorNum*2
 			for _, p := range s.state.Players {
 				if !p.IsOut() {
 					bonus := 0