The morality system in Mass Effect 2 is very similar to the one from the first game so your decisions will affect what other people think of you and how they react to what you're doing. Basically you're always allowed to choose between:
1) being an idealist (this means scoring paragon points)
2) being a renegade (this means scoring renegade points)
You can find out about your progress in becoming an idealist or a renegade from a karma bar found in the character screen - blue bar represents paragon points and red bar represents renegade points.
Earning paragon or renegade points:
The decisions of an idealist or of a renegade are made mostly during conversations with other characters. Answers located in the upper section of the dialogue menu are usually reserved for an idealist and the lower section of the menu is usually reserved for a renegade. Naturally you won't be receiving the same amount of paragon or renegade points for each decision you've made, because their amount depends on the importance of the scene. For example, a decision which involves saving lives is more important than being friendly towards someone and can result in receiving more than 10 points instead of the usual 1 or 2.
An interested thing to know about is that you can improve the process of earning paragon or renegade points by unlocking passive powers of each character class. Here's their list:
- A soldier can unlock a power named Combat mastery
- An infiltrator can unlock a power named Operative
- A vanguard can unlock a power named Assault mastery
- A sentinel can unlock a power named Defender
- An adept can unlock a power named Biotic mastery
- An engineer can unlock a power named Tech mastery
Developing these powers to level four can result in a 70% or in a 100% increase (depending on which option you've decided to choose).
One of many new features of Mass Effect 2 is an interrupt system and the idea here is that you can stop a scene by choosing a special action of an idealist or of a renegade. You should know that you won't be allowed to always choose between those two. Some conversations will have special interrupts reserved only for an idealist or only for a renegade and only in some rare occurances both interrupts will appear during the exact same conversation (Mordin's monologues are a great example here). Activating an interrupt is not mandatory, however choosing it usually allows you to achieve your goal much easier by saving someone's life (paragon) or by attacking enemy units prematurely (renegade).
Don't forget that you always have about two seconds to activate an interrupt after an icon has appeared on your screen. Choosing a paragon interrupt means pressing the right mouse button and choosing a renegade interrupt means pressing the left mouse button. If you miss the opportunity the conversation will usually continue, but you won't have a chance to retry (unless you load a previous save).
Interrupts always appear in the same areas, even if you've fully developed a paragon bar or a renegade bar.
Naturally you're free to choose whether you want to focus on developing only one bar or both. I would recommend that you focus only on one path, because doing so will allow you to unlock special dialogue options. Paragon dialogue option will appear during conversations in a blue color and renegade dialogue options will appear in a red color. If you see that a special response is unavailable (dark grey color) then it means you haven't sufficiently developed one of the bars. Special dialogue options are based on charm (idealist) or intimidation (renegade) and choosing them always makes the game easier. Some of the most common examples are skipping difficult battles, receiving discount from local merchants or being rewarded with valuable objects. If you fully develop one of the karma bars you'll also have a chance to convince some of the most stubborn characters to your point of view and you'll be allowed to resolve crisis situations (including confrontations).
Special dialogue options often appear during conversations. Blue answers are for idealists and red answers are for renegades.
Travelling through the galaxy:
Mass relays are used in the game to travel through the galaxy and each cluster (including the Omega Nebula where you start the main campaign) has one relay. Going through mass relays is free, HOWEVER travelling between different systems located in the same cluster (for example - between Sahrabarik and Kairavamori systems in the Omega Nebula) requires you to use fuel. There are a few things here you must know about:
1) You should purchase fuel (using a fuel depot) each time you plan on flying to a different system.
2) You should also consider purchasing probes (only if you want to scan planets for anomalies or resources).
3) You should always fly to a different system in a straight line to preserve fuel. After you've explored that system return to the one with the fuel depot.
Don't forget to refuel each time before planning a trip to a different system.
I wouldn't recommend allowing Normandy to run out of fuel while travelling within a certain cluster, because you would then have to agree to your ship being towed away to the nearest fuel depot. Naturally this service is not free so you want to have pay for it with credits or resources. Thankfully in most cases you won't have problems with running out of fuel as long as you remember to always return to the main system of each cluster. You'll also have a chance to purchase a technology which adds new fuel tanks and this may come in handy later in the game.
Exploring locations on foot:
Mass Effect 2 offers an entirely different experience when it comes to exploring planets, space ships or space stations. First of all, you should know that there are only five main areas in the game and they're the only ones you'll be allowed to visit any number of times. Aside from Normandy I'm also talking about Omega station, Citadel, Illium and Tuchanka. You'll want to return to these areas frequently to complete side missions and to purchase objects from local merchants (not counting Normandy).
All other locations are treated in Mass Effect 2 as mission areas and this mean you'll be allowed to visit them only once. Naturally this makes exploring them more important than before. It may sound like it's not a big deal when it comes to skipping a chance to collect resources or credits, however it also applies to scanning objects in hopes for acquiring new technologies. As a result I would recommend that you always move slowly and check each area thoroughly after you've defeated nearby enemy troops.
The game displays a mission summary window at the end of each quest and you won't be allowed to return to any of these mission areas ever again.
You'll encounter a lot of safes, terminals and locked doors during the course of the game and thankfully in Mass Effect 2 you won't have to develop any talents to ensure that you'll be allowed to get past these problems. This also means that you can start each mission even in the early stages of the game, however you may have problems defeating stronger enemies.
You can find out more about finding (and purchasing) technologies and collecting resources from the third chapter of the world atlas (Technologies) and you'll find a detailed description of each quest in the main section of the game guide.
This section of the atlas contain hints useful mostly to less experienced players, explaining some of the basic rules of taking part in battles.
Hiding behind cover is one of the key elements to survival in Mass Effect 2 and it's equally important as in many modern TPP shooters. Finding cover not only allows you to lower the risk of receiving major injuries but it also makes attacking your enemies much easier. There are a few things here you shouldn't forget about:
1) Taking cover behind objects is not an automated process anymore so you can't count on your character to automatically hide. Instead you'll have to press a corresponding key to force Shepard to go into hiding.
2) Don't forget that you're not 100% safe behind cover, because some of your enemies may change position often or even organize frontal attacks. You'll always have to be ready to change cover quickly or to stop using it at all.
3) I wouldn't recommend taking cover behind breakable things. Thankfully most of these objects are easily recognizable - they're mostly wooden crates. The only exceptions may present themselves during scripted boss fights (Grunt's personal mission is a great example here).
4) It's better to hide behind larger objects so you'll still be standing instead of crouching. This will lower the risk of receiving injuries while leaning out to attack enemy units. Some of the best examples here are walls and pillars - you can feel much safer behind them.
5) Some battles will feature explosive crates and containers and it's important not to take cover near them. This works both ways so each time you've spotted an enemy taking cover close to an explosive object you should blow it up.
Using cover is crucial to your success, especially while completing harder primary missions.
Mass Effect 2 is very different from the first game when it comes to handling guns, because instead of preventing your weapons from overheating you must now use coolant clips. Here are some of the important things concerning ammunition:
1) Standard ammunition clips which are a common thing on the battlefield will work with all types of weapons, so you won't have to search for any specific types. You shouldn't have any problems running out of ammunition. If you do make sure to examine bodies of your fallen enemies before moving on, because that's where you'll probably find new clips.
2) Power cells are a unique kind of ammunition for your heavy weapons and they'll also work with all types of heavy guns. You should know that there's a different multiplier for each weapon. For example, a dozen rockets for a rocket launcher may be equal to several hundred units of fuel for a flamethrower. All the calculations are done automatically each time you've switched your current heavy weapon to a different one, so you won't have to worry about it yourself.
3) I would strongly recommend purchasing or unlocking at least two or three technological upgrades which allow you to carry more power cells for your heavy weapons. You'll notice the difference later in the game, because you'll be allowed to attack more targets with a heavy weapon without the risk of running out of power cells.
4) There are several special types of ammunition in the game and you shouldn't ignore them, especially since you won't have to find any unique clips. All you have to do when you want to use a new type of ammo is to unlock a certain power (a standard one or a special one). Cryo ammunition is definitely the most useful one, because it allows you to freeze all types of enemies. Incendiary ammunition is also good, however it only works on organic targets.
Standard ammo clips and power cells can be found during missions, mostly near dead enemies and inside large containers.
Issuing orders to the rest of your team is very simple in the game and you should always remember that it's up to you to keep your followers alive. I would recommend that you start each battle with ordering them to take cover behind manually picked objects, because they may have some problems doing this on their own. Always observe what your opponents are doing and if you notice that one of your teammates has found himself (or herself) under heavy fire you'll have to provide assistance. Prevent your team members from moving alone into unchecked areas, because they may end up getting surprised by enemy forces. Don't forget that each time you've used a Unity ability you'll heal everyone around you, however you can only carry several medi-gels with you (this can be improved by unlocking certain technologies).
You'll often take part in longer battles and you should always consider dividing your team into two groups. One group (preferably both teammates or at least one) should distract your enemies by firing at them and the second group (preferably Shepard or Shepard with one teammate) should make a surprise attack from one of the flanks.
It's important to choose your followers carefully depending on the type of a mission you're about to start. For example, it would be a good idea to choose at least one tech specialist when you know that you're going to be fighting the geth.
Make sure to stop time often by pressing and holding the SPACE key. Doing this will not only allow you to examine the battlefield but you'll also have a chance to issue precise commands. You should also remember about creating shortcuts to certain abilities - they can be used not only to activate your powers but also to encourage your teammates to use their abilities.
Always have safety of your team in mind - this means ordering them to use cover and monitoring movements of enemy units.
Mass Effect 2 is a different game from many other RPG's, because in most cases you'll be fighting intelligent enemies. There are some monster encounters (mostly with varrens and klixens), however dealing with the beasts is going to be simple. There are five major groups of enemies in the game:
1) Poorly equipped enemy units - You shouldn't have any major problems eliminating standard enemies and you'll only have to be more careful while going against very large groups. In most cases you'll eliminate your targets easily even when using normal weapons and powers.
2) Well equipped enemy units - The only difference from the first group is their equipment. They may be using an armor, a shield or a slightly better weapon. For you it means that killing them will take more efforts, but it's still not something you should be worried about.
3) Elite enemy units - Each group of opponents has some elite units in its ranks and depending on the battle you may encounter only one elite unit or more of them. It's always a good idea to attack more powerful enemies before dealing with some of the weaker units, especially if they can attack you from a distance (Eclipse engineers), if they're carrying heavy weapons (rocket launchers, flamethrowers) or if they intend to close the distance separating them from your team (geth hunters).
4) Mini-bosses - They're not as rare as you might think, because each mission has at least one mini-boss. Naturally as you progress in the main campaign you'll encounter more of them. The biggest difference between a mini-boss and a standard enemy unit is that they're far more resistant - they're usually using an armor AND one or two shields. You won't have to attack every mini-boss as soon as you've seen him, however some of them will be trying to get closer and those are the ones that must die first.
5) Bosses - You'll only encounter several powerful bosses during the course of the game and to be honest they're all different from each other. There are only two bosses who appear more than once - Harbingers and Praetorians. Complete solutions on how to defeat each boss can be found in the main guide.
You won't encounter a lot of bosses in the game, however most of them will be tough to kill.
Other useful hints:
1) Each time you've encountered enemies with armors you should consider using incendiary ammunition or powers which work in a similar way. Each time you've encountered enemies using biotic or technological shields you should consider using powers from the same category (biotic powers to destroy biotic shields and tech powers to destroy tech shields). Overload is the best tech power for this kind of job. As for biotic abilities, you should be using Warp.
2) Some of your enemies will be capable of regenerating their health bars or shields and naturally you'll have to change your approach while fighting them - it's important to kill them during one coordinated assault, without giving them a chance to retreat and heal.
3) Always make sure to aim for the heads of your enemies, even if they're protected by different kinds of barriers.
4) Watch out for opponents using camouflage, because they'll want to surprise your team. Thankfully you'll encounter them only in a small number of missions.
5) Don't count on the fact that exploring an area allows you to secure it for the rest of the mission. It's a common thing for new enemies to appear out of nowhere or using previously unaccessible doors. You'll have to be ready for unexpected fights, especially while completing main missions.