OTTTD: Over The Top Tower Defense

Take command of HEROCORPT and launch a Preemptive Defense
CampaignT against parallel dimensions in OTTTD, the most
outrageous Tower Defense title.
OTTTD stands for Over The Top Tower Defense, and you'll see why when you're blasting 9 kinds of hell out of a floating robot shark that's making a beeline for your HQ.
You play as a commander for HEROCORPT, the 4th largest private military organization in the galaxy.
Your job is to "preemptively defend" the Earth against alien dimensions BEFORE they attack Earth. Make sure to come in under budget and fill out the TPS reports in triplicate!
Is "preemptively defending Earth" ethical? It doesn't matter, your responsibility is to the shareholders!