Survivalist

You start with three survivors and one road. Every gate is worth more the longer your squad shoots it — hold fire on a '+1' and watch it climb to '+20'. But gates come in pairs with a lethal pillar between them, so you have to pick a side: the '×3', or the '+18', and never the '÷5'. Break green crates to hit harder and blue ones to shoot faster, dodge everything solid, and kill what is coming down the lane. Every stage ends with a boss. Die, and it comes back weaker.