Only problem with UT4k is that I am having trouble passing the Assault missions
Well, here's some tactics/bugs that might help you.
First, hotkey your Shield Gun in an easily pressable key, because your going to need it. As soon as you reach an objective, switch to your sheild gun, crouch, and point the secondary fire in the general direction your getting fired at (with your back at the objective) This will lower the ammount of damage you take while capping an objective and buy you a few more precious seconds on the obj.
(You may want to practice on these maps by yourself to see what im saying)
FallenCity: <ATTACKING> The first obj in fallen city is pretty easy. There are two bugs you can exploit to kill the barrier. First, you can crouch next to the tunnel of junk and fire through the wall and hit the barrier. Also, you can choose not to drop down at all, go all the way to the right, and stand on a small peice of concrete jutting out from the cliff. Use your LG (lighting gun) to find a whole in the wall, then without moving your mouse, switch to your RL (rocket launcher) and start shooting.
There are a lot of barrels in FallenCity, especially near objs. Shoot them before you start to shield crouch on the obj so that your enemies cant.
The hardest objective is to Destroy the Gate Lock. The best way to reach it is to take the high road and destroy the turret from far away with your rockets (remember the LG-switch-RL trick) Then take out your sheild gun and run the length of the high part, and as you jump down, switch to your RL and start loading rockets (left click). If you press the right click when your ready to shoot the obj, theyll shoot in a nice spiral and all impact it together. Much more powerful.
<DEFENDING>
Here's two hints: On the Destroy the Gate lock obj, use the shock combo to kill those taking the high road.
Also, if your reallllllly stuck, theres a nice spam point on the last obj., its where the door retracts as soon as you complete the Gate Lock obj. You can't miss it, its a big hallway. Just sit outside and shoot shock combos in, and youll kill them one by one.
Glacier: <ATTACKING> You can jump on the supports and dodge down right in front of the door. Also, it may help to extend the bridge, if you can reach the lever. As soon as you get to the last obj, make sure you and your team forms link chains. If you link some one whose linking the tank, its a stronger link than if the two of you link the tank seperatly.
<DEFENDING>
2: You can see out the windows on the Activate the Ion Core obj. (obj number two thats that number) and you will know which hallway the enemy is coming through, so you can be ready with a shock combo.
3,4,5,6,7,8,9: Remember that the tank can shoot into the area your defending. It might be helpful to go ballistic against the tank. Grenades do the most damage, if your close enough. Try to stay on the opposite side of where the turret is facing, because it turns really slow. On the last (9) obj, remember that linking up with three or more people can decimate the tank. Also, you might want to kill the linkers who are healing the tank.
JunkYard: <ATTACKING>
1: You may want to over shoot the first obj to kill some of the players that layed the mines. If you kill the person, their mines blow up.
2: There is an AVRIL near the magnet. Use it to kill the turrets that protect the bridge
ALL: If you get really stuck, you may want to go out of your way to find the Redeemer near the drive-in movie theater to clear out an obj point. Also if you stand on top of a turret, it can't hit you and the person must get out to shoot you. When he does, steal the turret yourself and kill him
<DEFENDING>
1: Lay spider mines on the obj. Also you may want to take the air jumps to the turret near the magnet and shoot down in the valley. If you do, lay some mines around your turret because some people will try to come up and stand on your turret.
2: Lay some mines on the obj as well. Also, keep the turret healed with your link gun beacause youll need it for obj 3.
3: Lay mines on the bridge and use all turrets to your advantage.
4: Keep tabs on where the Hellbender is, it may take the magnet. If it does, try to link up to shoot it down.
5: Lay mines!!!!
6: Blow up the barrels by a large portion of scaffolding to make it fall down and block off a route. Then, you know what to do,
MotherShip: <ATTACKING> Remember that the primary fire of the fighter is instantaneous, so train your reticle directly on the enemy, dont try to lead him
3: Load up a vial of GOO in your BioRifle as soon as you get it while your running towards the obj. As soon as your in view of the bypass, launch the load. Massive damage.
4: I'm not sure why so many people have trouble with this. Just remember that the secondary fire of the shock rifle is your best friend. First, take out the one on the left by going down the ramp shooting shock balls at it. If the shock ball and the laser meet they cancel eachother out and you wont get hit. Also, keep dodging! The sentinal is a bot and fires at where you WERE. After the first one is dead, go back up the ramp (actually, youll probobly die a few times, so just respawn) Go to the ramp on the left again, but jump over the railing and land on a small, hardly visible lip on the other side. From here you can shoot down at the bottom most sentinal. Once that one is cleared, strafe along the lip and shoot the last one.
5: Sheild crouch
6: Load up GOO like you did in 3.
<DEFENDING> Again, remember that the primary fire of the fighter is instantaneous, so train your reticle directly on the enemy, dont try to lead him.
1: Theres only one entrance, so hover around it (where the flashing arrows are) and kill anything that gets near. Its hard for them to scirmish there because there are turrets shooting them as well as you.
4: Keep those sentinals healed with your link! Also, theres a spam point where they come in from where the bypasses were destroyed.
Convoy: <ATTACKING> Sheild Crouch on the objs!!!!
1: You can get on top by climbing up the car in which you start and jumping from car to car. Eventually youll reach the boarding platform and you can go down it. It also will help if you can capture the cache.
2: You have dynamite, so dont try shooting the door. Just shield crouch on top of it and get out of the way.
3: Sheild crouch
4: You can jump up the boxes on the sides rather than going up the ramps. From there you can jump to the obj and SHEILD CROUCH.
6: Shield crouch. You can ride on the top of the little car zooming around, and it will eventually take you to the Nexus Trailer. But you are a target. Also, you can jump over the railing on either side of the Nexus Trailer and run in rather than droping down the hole.
<DEFENDING>
1: The boarding platform regenerates when the enemy steps off it. If they get that far, you may want to charge up the primary fire of the sheild gun, it will kill an unsheilded person and throw the body of a sheilded person with its kenetic damage.
3: You can blow up that tanker in the middle to create a spam point, but dont count on it, it takes a while to blow it up and by then their already on you.
Robot Factory: <ATTACKING>
1: Use that LG trick that I told you about in FallenCity to hit the turrets from two spots where they can't hit you back. Both are on the railings near the spawn point. Use you LG to find them, then switch to another gun to kill it. It takes a while to destroy.
2: The Ion Cannon is a problem. Get into one of the tanks and destroy the link turrets. Then you can hang out by your tank spawn point and keep sniping the cannon with your shells. If you die, you just get expelled from the tank, only to take the next one that respawns.
3: You get a closer spawnpoint if you get past the underground doorway. You may want to just do run with the Sheild Gun and see how far you can get, so that your team gets to spawn in closer. When your getting near the data cables, load up your goo. Its almost dead in one hit. finish it!
4: You can shoot with your RL from outside in the hallway. When you get to the middle one, you can use flak to bounce back from the wall behind it because it has a shield facing you. You can't rely on the bounce back though, so try to get on the other side of the sheild.
5: The primary of your link cannon does a lot of damage. If you can form a link chain, it will kill it within seconds.
Wow. Did I write all that? cool. Umm yea so dont forget when your attacking to Sheild Crouch. Thats the biggest help in all the maps. Hope you can beat the single player! Onslaught is really cool. Heres a trick in ONS: If you get someone to deploy a Leviathan on top of a manta, you can fly around the map, but shoot like a deployed leviathan. (Most online servers have a patch for this now though) Enjoy!