Mobile Idle/Clicker Game Development
Idle games technically simpler than most genres but monetize better than many—if progression curve set correctly. Mathematics wins, not graphics.
Large numbers: working with Decimal and BigInteger
Idle games use numbers that don't fit in double. After 10 hours gameplay, player might have 1.23e+150 coins. double provides 15–17 significant digit precision, after which adding small sum to huge number simply gets ignored—player stops seeing weak generator progress.
Solution: custom BigDecimal or ready BreakInfinity.cs library (created specifically for idle games, works in Unity, 10x faster than standard BigInteger). Formatting: 1.23e+12 → "1.23T" or "1.23 trillion"—custom formatter with suffix dictionary.
Offline progress and honesty
Calculating offline earnings on next app open is standard. Important nuance: limit offline period (e.g., 8 hours max), otherwise player can "accumulate" 30 days and instantly pass all content. Premium offer "extend offline limit to 16 hours"—popular IAP in genre.
Save: current resources + last close timestamp + balance version. On load: offlineSeconds = min(now - lastClose, maxOfflineSeconds). Then earned = productionPerSecond * offlineSeconds. Production per second is cached, recalculated only on upgrade purchase, not every tick.
Notifications as retention tool
FCM scheduled notifications: "Your generators are full, collect resources!" On Android: AlarmManager via Unity plugin for precise timers. On iOS: UNNotificationRequest with UNTimeIntervalNotificationTrigger. Don't send notification before 2 hours after app close—otherwise annoying.
Timeline: basic idle/clicker with 20 upgrades, offline progress, monetization—6–10 weeks. With seasonal events and extended progression—3–4 months.