A massively underrated game deserving of a fair chance.
There are two factions in this war; The Principality of Zeon, humans who live in space colonies, and the Earth Federation Forces, a coalition of Earth-bound nations. This game covers only the Earth-based portion of the war, beginning shortly after the space-faring Zeon has invaded the Earth and continuing to the conflict's closure (the game follows Gundam canon regardless of which faction you pick or how you perform; there are periodic updates on the war in general and specific operations in other parts of the world and in space that Gundam aficionados will recognize). Picking a faction gives your pilot access to different mobile suits and different AI teammates, as well as opposite mission objectives.
This game follows a day based structure in that once loading or creating a game, one is brought to a new menu screen. Here the options are to embark on a Mission, check on repairs or upgrades of mobile suits in the Hangar, request additional pilots or new mobile suits from the Supply, save or load game data on your System, see in-depth statistics on pilots and mobile weapons under Data, or simply move ahead to the next day. Missions have deadlines, meaning that after certain dates, they are no longer available; one can pick which missions they embark on and ignore others, though there is little consequence. On different difficulties, deadlines are closer, putting more stress on completing them in rapid succession if you don't intend to skip any.
Mobile suits are customizable in the Hangar in a number of ways; you can upgrade their defense, their attack prowess, their weaponry load-outs and ammunition, or their environment type to give boosts in certain areas. Mobile suits are allowed a main weapon, used by the square button when in combat, and as many as two sub-weapons, which are accessed by either the circle button or R1. I've yet to come across a mobile suit without a melee attack activated by the triangle button.
Mobile suits take damage during combat; that much is obvious. But in combat, different parts of mobile suits take damage as well. This means that you can effectively disable an enemy by taking out their head; this will send them over the edge and destroy them at first, but on later difficulties, it'll only give you the advantage of reducing their accuracy. You can take out a mobile suit's legs to reduce them to a slow limp and cut down heavily on their mobility. Taking out a mobile suit's arm will prevent them from using whatever weapon it held, or take from them their shield. A tip to new or future players; when your on shield has been taken out, you can still use the L2 button (the button your shield is typically mapped to) to cover your midsection and cockpit with your other arm. Damage taken directly to the cockpit block will result in the rapid destruction of your mobile suit, regardless of how many other parts are still in the green.
After a brutal combat, mobile suits will appear in the hangar as in Repair, Breakdown or Critical; this means that you won't be taking them out today. Moving forward a day will often be enough for suits already in Repair, but Critical suits can take days to be usable. This means it pays to have a back-up unit waiting for you int he event that a mission deadline is rapidly approaching and you have doubts of your main unit's ability to be ready in time. Sometimes, it won't matter that you have a back-up mobile suit waiting; if you've taken Critical damage, in reality barely surviving the mission, your created pilot's status will be set to Critical, representing injuries acquired in your last sortie due to cockpit damage. Embarking into battle while your in Critical condition is a bad idea; I have yet to do so, and can't speak for whatever consequences there may be.
All throughout your playtime, on specific dates, news of the war will come filtering in from your superior officers, and it will be quite unsurprising to see the end coming. Once you have completed the game, your given the option to start again with the same pilot on a different difficulty with all of your mobile suits and pilots and their upgrades. Once you've done so, you'll be given the ability to request a number of mobile suits of the other faction, representing units your faction has captured. Chances are that you'll want to continue play in your upgraded mobile suit. Starting over again will allow you to experience missions you may have skipped the first time through, especially considering that a first time player's funds may not be high enough to request a second mobile suit for use on a mission with an approaching deadline in the event that their primary unit is out of commission.
Starting out, I recommend creating a pilot with the E.F.F. for a first time player, and without a doubt, the Easy difficulty. It has been said before that Normal is 'murderously difficult' and that's no lie. Enemies are tougher, and deadlines shorter, meaning that, assuming one can complete missions, they'll no doubt be forced to skip a few over the course of the campaign. It stands to reason that mobile suit requests are more expensive on higher difficulties, but I can't say for sure if this is true. The reason I recommend the Earth Federation Forces for a new player is that they have access to beam weaponry earlier in the war, and as a novice Zeon pilot, beam weaponry WILL tear your unit apart. Additionally, one of the first and most common mass produced grunt type units for Zekes is the Zaku II, a balanced enough machine. The Zaku II has a shield on its right shoulder covering the primary weapon's arm, but the Federation equivalent, the mass produced RGM-79 GM has it's shield mounted on the left arm facing outward. I'll explain why this is important as I point out some beginner tips and tactics.
When engaging an enemy in most games featuring guns, it's best to strafe; this holds true here as well. One will typically want to lock on to an enemy in range with the L1 button and then strafe, firing on them. Typically, if facing a moving target, you will want to move in the opposite direction; for some reason, it seems as though your shots will have a much better time connecting with the enemy if you're not moving in the same directions. When strafing, you will want to try to keep your enemy on your left, especially when piloting a GM; this is because most units have their shields mounted on this arm, rather than the one that holds their primary weapon (although mobile suits may be inherently ambidextrous, their pilots aren't), and your shield will catch the majority of rounds headed toward your cockpit block. With the Zaku II, you won't be able to strafe like this, as your unit will have to turn its body to shoot. If you try it for yourself, you'll see exactly what I mean, but the bottom line is that you'll be exposed to a significantly more damage starting out as a Zeke pilot as opposed to a Feddie. Two more tips before moving on; if you have head or chest vulcans, use those secondary weapons to take out tanks or planes instead of wasting more powerful primary weapon ammo, and always keep moving.
This isn't a difficult game to control, especially once you get a feel; you'll generally want to keep moving, firing at enemies you've locked onto, but you do have the ability to open the Sniper mode when stationary by pressing R2. You can zoom in to x12, as well as target enemies in specific locations. The downside to this ability is that enemies in range will fire on you as you stand motionless, disrupting your aim even if they don't damage you significantly, and your basic weapons' bullets will take too long to reach where you're aiming to hit a moving target without a lot of careful aim and leading. This mode is better suited to suits with heavier weapons like a Guntank, or just about anything you've outfitted with a 180mm Cannon or Beam Rifle. Don't expect to use this a lot, though it is handy for locating enemies, since it features markers directing your view towards enemies.
Mobile suits control exactly like giant robots, so don't get mad at your inability to handle it like a sports car in GTA. If you know the controls, you can handle most any situation; the X button handles your units' boosters (I've yet to meet a mobile suit without boosters), allowing you to move forward, backwards or to either side quickly, or hover for a brief period of time. Mobile suits are inherently slow, the primary walking speed of a Zeon officer's unit is only around 99 km/h, but missions are short so don't expect a lot of slow travelling around the also small maps, even though later in the game. One will often want to use boosters to get away from sticky situations, and one will frequently need to stop in for a resupply of ammunition while on missions. Another tip; try to resupply after every skirmish, or as frequently as possible, since disengaging from an enemy when you're out of ammo can be very difficult, though you will have melee available.
This game isn't one of the best looking games around, but the mobile suits do look pretty fantastic, and the rest is serviceable. I've heard reports of unplayable framerates, but these seem to be disc specific, so try again if that's the case; this game has always worked for me. Some levels at certain times of day do have lower rates but I've seen only one such.
In short, give this game a chance and I'm sure you'll find it's nowhere near as bad as people say, and may in fact be a fun and addicting experience, even if you're not a series fan.