Author: John Watson Author Email: [email protected]. Gravity Ace is a 2D multi-directional gravity shooter (cave-flyer). It's a love letter to Thrust and Gravitar and all of the amazing games they inspired. Descend into dark caverns, fly and blast your way past enemies, retrieve the reactor core and make your escape, all while fighting the deadly embrace of crushing gravity. Do you have what it takes, pilot? You are the Pilot, a volunteer in the United Earth Navy, assigned to the U.E.N. Hornet, a new ship with an experimental engine that allows it to warp behind enemy lines. Launching your small fighter craft from the Hornet, your mission is to sabotage the enemy by raiding their bases and disrupting their power supply network made up of reactor cores connected through hyperspace.