While being underwater slows things down, it adds a few interesting and enjoyable twists to the gameplay.
Under the broad heading of action games, there is a relatively rare subgenre known as the underwater game, and Sub Rebellion is an example of this sort of title. In this mission-based shooter, you'll pilot the advanced submarine Chronos through the murky deep, and as one might expect, things move a bit more slowly in Sub Rebellion than in the typical action title. But while being underwater slows things down, it adds a few interesting and enjoyable twists to the gameplay. Although you'll find few frills in the actual presentation, the end result is largely worth it, and many players will find the game to be an enjoyable experience.
In the world of Sub Rebellion, most of the planet's surface is underwater, and submarines are the preferred mode of transportation. The military-industrial complex has taken advantage of this fact to seize control of the world by force, but their harsh methods have given rise to a rebellion. In the grand tradition of video games, you pilot a single vehicle so powerful it can shift the balance of power by obliterating scores of enemy subs, taking out gigantic bosses, and laying waste to enemy bases. The story isn't terribly original or complex, but it's integrated fairly well into the game.
At your headquarters, you'll be provided with a variety of options that you can access between missions. You can select from several control settings and view video tutorials before setting out on a mission on the world map. When you've completed several missions, you'll be able to browse through the undersea treasures you've acquired and buy and equip weapons, shields, different paint schemes, and more. There are seven important aspects of your sub to configure, and the different kinds of equipment are suited to different situations. In most cases, one engine won't completely outclass another--for example, a particular engine may have a slower top speed but a faster turn speed. The dry shield is tailor-made for missions where you'll spend a lot of time on the surface. New items will become available for purchase as you complete missions and find more treasure. Customizing your sub quickly becomes one of the most interesting and enjoyable aspects of the game, and it gives you incentive to press onward through missions and acquire more buried relics.
It's unfortunate that the tutorial portions of the game aren't interactive, because the controls will take a bit of time to get used to. There are three available control settings, all of which rely on the controller's shoulder buttons for movement. One set is mapped to forward and reverse, while the other controls ascending and descending. The face buttons are used for fire control and surfacing functions, while the left and right analog are used for positioning the nose of the sub and controlling the camera, respectively. Because you'll need to use two hands to maneuver your sub effectively in combat, you'll seldom find time to reach for the camera controls. This doesn't matter much in the end, however, as you're given a wide and effective view to begin with. Pressing the select button will toggle between a third-person perspective and a first-person perspective. The former is more useful for dodging enemy fire, while the latter provides an unobstructed view of your surroundings and sonar readings.
The cleverly implemented sonar, which is mapped to the X button, is crucial to gameplay. When you tap the button, you'll hear a familiar ping and see the immediate area mapped out in wireframe. Landscape and objects are displayed in white, enemies are displayed in yellow, and treasures are displayed in purple. Within a very short time, the game will have you pinging the sonar every couple of seconds. Sonar will allow you to see through several layers of rock, meaning you can target and attack opposing forces with torpedoes even if you don't actually have a line of sight. More than anything, this defines the gameplay experience.
Your craft will carry two sets of weapons at any given time: one for underwater combat and another for surface combat. Each set is composed of one short-range weapon and one long-range weapon, and the functions of both are more or less identical. As in many 3D shooters, you'll be able to lock on to multiple targets at once by holding down the fire button while aiming at a target. The time it takes to acquire a lock is contingent upon the distance between you and the target and the type of weapon being used. Additionally, each weapons system is capable of firing a certain number of homing projectiles at once with different techniques and tracking effects. The frag torpedo system fires a large torpedo, which in turn releases five smaller ones with high speed and a strong tracking effect. Prox torpedoes are a bit slow but can damage surrounding targets with a large explosion.