Gotham City Impostors

To get this achievement you have to win on all 5 of the maps that came out with the game and win on all of them on each game mode. You do not need to win on the dlc maps just the ones listed below.

The maps that you need to win on are:

Ace Chemicals
Amusement mile
Crime Alley
Docks
Gotham Power

The game modes that you have to win all these maps on are:

Team Deathmatch
Fumigation
Psych Warfare

To clarify you do NOT need to be level 35 to unlock this achievement, you can make progress before unlocking the game mode feats and still get this achievement without replaying maps.

So as the game has become a lot more broken and it suffers so much from connection issues, there have been some discoveries I've made whilst going for this achievement which I'd like to point out.

Requirements For This Achievement

In order to get this achievement you need to win an online match on all of the default maps in each of the default game modes that were originally available in the game.

Maps You Need To Win On

Ace Chemical
Amusement Mile
Crime Valley
Docks - Glitchy Map - May Disconnect Players Or Teams At The Start Of The Match
Gotham Power

Maps You Don't Need To Win On

Arkham Asylum
East End
The 25th Floor

Game Modes You Need To Win On

Team Deathmatch
Fumigation
Psych Warfare

Game Modes You Don't Need To Win On

Bounty Hunter

Keeping Track Of What Maps You Have Won

Now unless you have a pen and paper and you write down what maps you have won in each game mode, there is no way in which you'll be able to figure out what maps & game modes you have won towards this achievement and you may be repeating yourself multiple times on the same maps and game modes if you decide to boost as well as play legit.
The reason is because when you reach Level 35, you will have a feature unlocked in the "Feat Of Prowess" that allows you to keep track of what game modes and maps you have won. However if you have won any of the maps and game modes before you reach Level 35, none of them will be registered on the screen but will count towards the achievement. So keep this in mind when you are going for this one.

Organization

In order for you to boost this achievement you will need to have at least 12 people including yourself which can help you. Particularly the Fumigation and Psych Warfare game modes since there is never enough people to start-up loads of the matches, although randoms still play these game modes time to time. Having 12 people will prevent randoms from joining your lobby but you can do this achievement with less (randoms can join though). But it is advised you create or look for boosting sessions to help you.

If you are the host for the session you will need to organise the parties in a way which suits you the best. I personally put the group in 2 different parties with 6 people each. At the same time you will need to find 2 people (or 1) that are willing to host an in-game party. It is suggested to have one of them in a different party than yourself.

Once you have the 12 people arranged, the people who are hosting an in-game party need to press the in the Main Menu of the game and then press to Start a Private Party. They can then invite everyone in the party by pressing or using the guide and then going into the XBox Party. If all 6 people are connected to each other it means they can play along. If however someone cannot connect to your party, that player may need to restart the game, XBox or router or worst case scenario, swap teams.

Now before we carry on any further, let me strongly suggest that whoever is the host of the session get's a pen and paper and writes down what game mode they wish to work on first, then write down the 2 teams which are in the session, all 5 of the default maps and then lastly put in boxes underneath the teams names and tick them when a specific team has won the match.

When everyone is in position and ready, the 2 party leaders need to communicate with each other and get ready to search for one of the game modes. Since they are the host, they will take the remaining people with them wherever they go. Once they have searched and found each other, the 12 people should lock the lobby and prevent randoms from joining.

Now something you need to take note of is that if you are the in-game party leader and you search for the game mode, you will likely be the host of the match. However this could change depending upon which party-leader between the 2 of you has the strongest connections. When playing a match online, if any of these leaders quits the match, then everyone in that party will go with the leader as well back to the main menu. Keep this in mind for some of the game modes.

Now the map that loads up in the game mode you are playing will be random and the Veto system ( to vote) doesn't always work. So if you don't have the map you wish to play on, or a DLC map (Arkham Asylum, East End & Gotham Power) then I suggest the leaders of the parties press the button to back out and return to the previous menu. Make sure everyone in your in-game party are back at the main menu by pressing the button and checking their status's.

Once you have got the map you want to play and win/lose let it load and play away.

Psych Warfare - Boosting

Among the 3 game modes, Psych Warfare is the longest to boost with a group. It will take a couple - a few hours to get done. There are however 2 boosting methods which you can do in this game mode.

Method 1: Play The Match To The End

This is the longest of the 2 methods, but it guarantee's the team that's winning the match as everyone will remain in the game mode (unsure of Docks though). Another drawback though is that 2 rounds need to be completed and they are 6 minutes each.

First decide which team is winning the match on the map, once decided get that team to pick-up the battery and plant it into the device. When the machine is activated the losing team will go into Slap Happy mode and then the winning team will score a point. To avoid frustration and confusion, get the losing team to stand where the winning team's battery is and either get the winning team to get kills or get the losing team to get Slap Happy kills when the machine is activated. They can also work on this achievement at the same time...



Rinse and repeat in the 2nd round and complete the match, making sure the winning team has enough points to get them ahead for the win.

Method 2: The Glitch

I originally wanted to try out this method and I'm pleased to tell you all that it works! The only drawback is that you need to do some co-ordination.

First, you need to find out in the lobby between the 2 leaders who is the host. Remember the host of the lobby will likely be the one who enters the lobby with their group of players first. Once you know who the leader is that team can take a win.

Start the match and get that team to pick-up the battery and put it in the device to score a point. As soon as the timing sequence for the Slap Happy Mode is complete, get the leader of the other team to press , choose Exit Match and confirm. Now that leader and the remainder of the team will return to the main menu, but because the other team left behind will have 1 point scored and no other players left... the game will give this team a WIN!! This makes this game mode much easier and quicker to do.

Whilst the winning team celebrate this victory, the other team can quickly search for another Psych Warfare match and hope that their in-game leader becomes the host of the match. Then the previous winning team will either end up in a lobby with them, or if they end up on their own, simply get that leader to press to return to the main menu and then re-search Psych Warfare for the match the other team are based in.

Wrong Team: Sadly this game has no prediction as to which one of the 2 leaders in the match will be the host, unless you know for certain sure which team joined the lobby first. And if you do the above method and the wrong team quits the match, then everyone... including the other host and group of players will be returned to the main menu and no one will get a win. And you would have to re-search and find the same map and try again. So keep this in mind when you are going for this achievement.

Fumigation - Boosting

Among the 3 game modes, Fumigation will probably be the easiest and quickest to do. Not many randoms like playing this game mode because it goes fast.

When the match loads, decide which team is taking the win and then once decided, the winning team simply captures all 3 objectives on the map and then let the score limit go to 100. That's all you need to do for a win.

To make things simple, I suggest the winning team gets the kills in the match and the losing team runs around and gets killed by a player on the winning team.

You can also attempt to get this achievement as well...



Team Deathmatch - Boosting

There is no real easy method in boosting Team Deathmatch because the game mode is still popular to date. Chances are that if both teams searched, they will end up being in different lobbies with random players.

With total honesty, I suggest Team Deathmatch should be done legit with just yourself or a handful of players in the group against the bots. But be-aware that some players will be around Level 100 - 1000 and they sure have commit themselves to the game. Having said that though if you were on their team, you have a high chance of winning the map you want to get a win on.

If you still wish to boost this, I suggest you keep on searching until somehow you end up in a lobby together with all 12 players in your group. Now when you have all paired up, stay together and play any map that appears. The simple reason is if one team leaves and re-joins, randoms will easily take the spots and you will have a nightmare again trying to find each other.

If the match loads with your boosting group or with anyone, the objective is simple. The first team to reach a total of 75 Kills wins the match.

Disconnections

Sometimes when you start a new match or you play on a certain map (most notably Docks), you or one of the other players on your team may get disconnected from the game, XBox Live or even automatically placed on the XBox Dashboard. If the player has been disconnected to the main menu then you can re-invite them by using the . You'll have to do this quick though before randoms join. Having said that though, if you are not the host of the party the game will attempt to re-connect you with your team. This cannot be done if you are disconnected off XBox Live or on the Dashboard.
If all else fails and a random player manages to join your match then the recommendation is to finish the match as quickly as possible and then get the host to return to the main menu. By doing this they will take all the players that are in the same team as them and then they can re-invite anyone into their game party that's missing.

Note: If you are the host and you get disconnected from the match and returned to the main menu then your team will get disconnected and returned to the main menu as well. They will however remain in your in game party. If however you are disconnected from XBox Live or returned to the XBox Dashboard then your party will be removed from the match and will be returned to the main menu of the game, without being partnered up with anyone else.

Good Luck!