From the publishers website and press release:

This is the first entirely new game system from ADB, Inc., in years. It brings infantry combat in the Star Fleet Universe to life in a way that allows ground battles to be fought simultaneously with the space battles portrayed by Star Fleet Battles, Federation Commander, Starmada, or A Call to Arms SF.

Over 500 unit counters portray squads of five Marines, snipers, engineers, commandos, and heavy weapons; or individual tanks and vehicles; or special game markers.

The very simple “shoot then move” system reflects the savage horror of war at bayonet point. Fast interaction is created by rules for opportunity fire and defensive snapshots, so both players are constantly acting, reacting, planning, and making hard decisions. Do you fire at those Klingon troops attacking your right flank — or hold the fire of your weapons for the main attack that has yet to appear (and might never)?

The full-color highly artistic map portrays the terrain on a typical planet far, far away, but rules allow you to designate the colored areas as crops, forest, swamps, marshes, or any of a dozen other types of alien landscape. The map even includes an active volcano and a river of lava!

Each counter is a group of five Marines (i.e., a "Boarding Party" from SFB or a "Marine squad" from FC, facilitating interactions) or a single vehicle (tank, ground combat vehicle, shuttle, or whatever). Each hex is 100 meters. While you can stack a lot of units in one hex (more infantry than vehicles, but still a lot), only a few can fire out of that hex in each direction.

The game system is one of player turns. On your turn, each of your units can either shoot or move, not both. Shooting comes first (after which the unit is turned upside down so that you remember not to move it), then movement, then you turn all of your upside down units right side up. When you shoot at an enemy unit, you cross-index the kind of unit that is shooting with the kind of unit being shot at, adjust this for any terrain that provides protection, and roll one die. The enemy unit might be destroyed, stunned (turned upside down so it won't be able to shoot or move on its next turn), or unharmed.

The first game module, SFM: Assault!, includes Marines, other infantry (commando, heavy weapons, engineers, Prime Teams, militia), and vehicles (tanks, trucks, engineer vehicles, command vehicles, and various light-armored troop carriers).

Units will be able to dig in, call for regular artillery or transporter artillery, do assault landings with shuttles or transporters, do close assaults, use opportunity fire to shoot during the enemy turn, and conduct air strikes with fighters or gunboats.

Star Fleet Marines: Module I – Assault