Unlockable: Play Again
After beating Mass Effect, you can play through the game again, with the same character, same skills, items, et cetera.

Unlockable: Higher Levels
You can increase your maximum level from 50 to 60 if you beat the game once through and opt to use your character from the previous game in a new game.

Unlockable: New Skills
If you beat the game and choose to replay the game with the same character, your character type will be able to learn some skills he or she would otherwise be unable to learn. For instance, on a second play-through, Adepts can learn to use Shotguns, First Aid, and other skills they were otherwise unable to use the first time through.

What's written above is somewhat accurate, but not completely. You must actually unlock specific achievements associated with weapons and skills for them to be unlocked for all character classes. For instance, for Adepts to be able to learn to use Assault Rifles, you must unlock the achievement that asks you to kill 150 enemies with the Assault Rifle.

Hint: Infinite Credits
Here's a great way to score infinite Credits. Follow the steps below in order to do so...

1.) First, fulfill the side quest involving Dr. Michel (from the Med Clinic) and her blackmailer. After the quest is complete, you'll get a discount from all of the goods she sells.

2.) Start selling her all of your expensive equipment. Then, travel to the Wards Markets and talk to the merchant named Expat. You can buy all of your stuff back for cheaper than you sold it off.

3.) Head back to Dr. Michel and sell off your stuff again. Repeat this process as much as you want for as much profit as you desire.

Hint: Infinite Paragon and Renegade Points
Here's an effective and foolproof way to score infinite Renegade points. When you get to the part of the game where Lorik Quinn is going to testify against Anoleis, speak to Lorik Quinn and convince him to testify. This will give you twenty-five Renegade poionts. Then, walk away from him, return to him, and ask him something unrelated to the case. You'll then be given the option to "Answer another question", at which point you'll be able to convince him to testify again, for another twenty-five Renegade points. You can repeat this indefinitely until you score the amount of points you want.

You can get Paragon points using the method as well, just as easily as you can get Renegade points. Just select the blue-colored (Paragon) option instead of the red-colored (Renegade) option, and as before, you can do this over and over again as desired.

Hint: Infinite Experience
Head to the freighter on Feros (in the Zhu's Hope Colony). You'll find a computer terminal here that, when decrypted, will alert you to investigate supply shipments that have diverted course in the Voyager Cluster.

Quite simply, if you then save your game, and subsequently reload it, you'll be able to decrypt the computer again for the same information you just got. This is a slow, slow process, but it is a real way to have access to infinite experience points. If you have the patience to do it, give it a go.

Hint: More Infinite Paragon Points
Here's a good way to get infinite Paragon points, if you so desire. Do the side quest entitled UNC: Lost Module. During this side quest, you'll need to find a creature which has the missing module. Search him for it for the first time, and get six Paragon points. You can then continuously search him over and over again for more Paragon points. It's completely unlimited.

Hint: Earning Credits
We have an "Infinite Credits" cheat here on IGN Cheats, but if you want to collect money rather easily (and honestly), try undertaking one of the five major fetchquests in the game (all UNC): Asari Writings, Locate Signs of Battle, Prothean Data Discs, Turian Insignias, and Valuable Minerals. These missions combined, if you were to collect everything above and beyond the limit provided to complete the side quest, are worth in excess of 5,000,000 credits, more money than you'd really know how to spend in the entire game.

Hint: Mako Repairs
If you want to repair the Mako but don't want to waste Omni-Gel doing so (or you simply don't have the time to waste waiting for the repairs to process), you can always press X and opt to return to the Normandy. It will inconvenience you since you'll be reinserted in a specific place when you decide to go back to the planet in question, but your Mako will be fully repaired for reinsertion.

Hint: Lose the Mako
If you're driving around with the Mako on any planetary surface, whether on a side quest or during the game's main missions, you can use the Mako's machinegun and missile launcher to do massive damage to enemies. However, the extra power of the weapons means easier kills, resulting in lower experience points. If you want to get more experience (twice as much, in fact) get out of the Mako to kill enemies. You can weaken them as much as you want with the Mako, run them over, pin them down, and more. But be sure to deliver the killing blow outside of the Mako to maximize how much experience you will earn from the kill.

Hint: Prestige Classes
There are six Prestige Classes in the game, and only two are available to any one class. To unlock Prestige Classes, you must get your character to level twenty. Then, head to the Normandy's Galaxy Map and travel to any system. At this point, Admiral Hackett will contact the ship and ask you to help him with something, unlocking the side quest UNC: Rogue VI. This side quest takes place on the Earth's moon. Complete the side quest to open up the two Prestige Classes available to your character, but choose wisely! Your choice is permanent.

Below are a list of each base class and the two Prestige Classes available for that class. Keep in mind that there are crossovers, so that each class will share one Prestige Class.

Adept - Bastion, Nemesis
Engineer - Medic, Operative
Infiltrator - Commando, Operative
Sentinel - Bastion, Medic
Soldier - Commando, Shock Trooper
Vanguard - Nemesis, Shock Trooper

Hint: Game Completion Duplication
After completing the game, you're able to restart with your character equipped with everything he had in the prior mission, as well as retaining experience, credits and more. However, there's a strange duplication anomaly present that is worth mentioning. If you take a look at your inventory, you'll notice that there are copies of what you're wearing (armor, weapons, modifications) in your inventory and equipped on you. Nifty!

Hint: Thresher Maw Tactics
Thresher Maws, which are located mostly on uninhabited or barely-inhabited planets, can be pesky foes. The best way to take care of them, as most people know, is to circle their locations as you pound them with machinegun fire and rockets from the Mako. However, Thresher Maws disappear underground and reappear near your location, and can at times reappear underneath you, instantly killing you (or leaving you dangerously close to death).

A great way to avoid this is to drive the Mako over elevated terrain as you fight these foes. Thresher Maws can only burrow underneath flat terrain, so elevated terrain is off limits to them. If you remain on elevated terrain as you fight them, they won't be able to respond to your attacks with attacks of their own.

Hint: Infinite Experience II
During your first conversation with Liara, you gain experience when you’re done speaking with her. If you reload your save after the conversation, you can actually speak to her again and get that experience one more time, over and over again. Depending on where you are in the game, this conversation is worth about a thousand experience points, so it’s quite a lucrative conversation to partake in over and over again.

Hint: Save Your Points (Charm/Intimidate)
If you’re willing to play the game over and over again using the same character, there’s a way to save about twenty skill points. Your Intimidate and Charm ratings are automatically upped when you become a Spectre. If you play the game over again, and over again from there, your Charm and Intimidate skills will slowly increase as each play-through grants you Spectre status. This will thereafter allow you to put the points you would normally spend on Charm and/or Intimidate on something else, making your character even stronger.

Hint: Wear Any Piece of Armor
Armor in Mass Effect is created for specific types of creatures and classes. However, there’s a way around that so that you can get any character to wear any piece of armor. To do it, try the following technique below.

1.) Head to the equipment menu and head to the character you want to re-equip, finding the piece of armor you want him or her to wear regardless of the character’s race or class and regardless of the armor type.

2.) Including the piece of armor you want to equip, count down the pieces of armor to the bottom of the inventory list.

3.) On any piece of armor, click the upgrade option. On any upgrade, opt to turn it into Omni Gel and then quickly opt out. This should return you back to the upgrades menu. Count down from the bottom of that list the number that you earlier acquired when you counted down on the armor list. Now click on that upgrade and transfer the upgrades by hitting yes.

If done properly, you should now be equipped with the desired piece of armor regardless of type.

Hint: Easier Aiming
If you want to have an easier time shooting and killing fast-moving enemies such as Geth Hoppers, Geth Drones, and the like, try the following. Open up the command wheel when engaging them in combat. This will freeze the game, but you’ll still be able to aim your gun at foes all the while. Aim at the fast-moving enemy and then get out of the command wheel. This will score you direct hit after (admittedly cheap) direct hit!