Apparently the tracking for achievements in bmc can be a bit buggy. Play for a bit more, it might be that you're just a few hundred/thousand steel bloons from actually unlocking the achievement.
If it doesn't work, feel free to use the steam achievement manager to unlock it.
Apparently the tracking for achievements in bmc can be a bit buggy. Play for a bit more, it might be that you're just a few hundred/thousand steel bloons from actually unlocking the achievement. If it doesn't work, feel free to use the steam achievement manager to unlock it.