You are now ready to download Mecha Fortress: Idle Titan War for free. Here are some notes:

1. Click “Install anyway (unsafe)”, if your phone does not allow installation, this is because the Android system blocks it.
2. If there is a message like “incompatible version” most likely this version is ARMv7, it does not support many new phones, try to find another version (ARMv8, ARM64)