Some of the following information comes from my trip to Toy Fair; other details were provided by Rob Daviau, a game designer at Hasbro.
The warriors include 30 plastic figures, including World War II soldiers, furturistic robots, medieval knights, a large dragon, and many more. Each unit (some units are one figure; some are multiple figures) has its own card that controls both movement and combat strength.
There are 85 tiles of terrain in the game. Some terrain tiles are large (up to 24 hexes) while others are small (1 hex). There are water tiles, sand tiles, rock tiles, and grass tiles (in roughly increasing order). Many different battlefields can be built by attaching and stacking the tiles.
The rulebook will feature two games: a basic version and a master version. In the basic version, designed for younger players, characters move, attack, defend, and have range -- but there are no special powers and some other rules are minimized and/or eliminated. The master game includes special powers, wounds, engagement rules, falling rules, and a few other additions.
A battlefield/scenario book shows how to build five battlefields, layer by layer. Each battlefield has two scenarios. (Three of the five have a basic and a master scenario, while the last two only have master scenarios). The goal of each scenario is different. Sometimes, you'll be trying to eliminate all opponents. Other times, you'll try to get to a certain space, protect a certain figure, or hold out for a certain number of turns.
Each unit has a movement rating ranging from 4 to 7, which is the number of hexes you can move on a turn. However, moving up a level counts as a hex, so moving from one hex to another that's two levels higher costs three (1 over + 2 up). Moving down does not incur that penalty (so moving back the next turn would just cost one). However, if you move down more levels than your height when moving from one hex to another counts as falling and you might take damage (unless you are falling into water).
There are some twists, such as flying creatures and vikings, who have a chance to do a berserker charge each turn and move twice.
Combat in the game is fairly straightforward. You roll attack dice as listed on your unit's card (2 to 6 dice), and the opponent rolls defense dice equal to the number on their unit's card (2 to 9 dice). Extra hits count as wounds.
Squad figures have one wound each, so a single hit kills the figure. Heros (one per character card) have wounds ranging from 1 to 5. You get advantages for high ground and special powers.
As far as establishing the initial teams, the basic game tells you which figures are on which side and where they start. The master game uses a point system in which players alternate drafting cards until they reach the pre-assigned point value for the scenario. It's possible to bring a "pre-fab" army to the battle in order to save time.
The basic game is for two players. The master game is for 2 to 4 players.