Beat the campaign
The campaign will take you a couple hours to beat on the lower difficulties, it is not too difficult. The final level is called Armageddon.
Build a 10x10 weapon (on any level other than Mega Blocks)
This is easiest with two controllers. set up the second controller, choose the beach level and set the blocks to red and blue only. Build using only the blue blocks. Make sure to protect your opponent's block because if it gets destroyed, the game will end. NOTE: the frame that you have is 11 spaces wide so 10 is all but one of them.
King of the Mountain
Beat Mountain Top 1
This is fairly easy, make sure you punch the orb-like-thing in the robot's chest so your blocks can do damage to him.
Beat Downtown 2: The Skyscraper
Be sure to be building constantly all of the way up to the top. The weakness of this boss is his cloud. Fortunately with him, when he is off his cloud , he can not attack so as soon as he is back up, hit his cloud again.
Man vs. Machine
Win a 1v2 battle against 2 Hard CPs
This is a very difficult trophy and requires a lot of practice. Whenever possible, try to take down one of the CPs to even the odds. Also, whenever you see a ninja, kill it, it will help out a lot.
Knock out 20 opponents without dying in a single match
This is not very difficult. The easiest way to do this would be to mash
repeatedly causing you to be pretty much invincible.
Get past the enemy hoard in Armageddon without dying
This one is a lot easier than it may sound. Especially on casual. Just be sure to use your shield and familiarize yourself with enemy attack patterns and pick them off before they get a chance to destroy your block.
Battle is Best
Play 25 Battle Mode matches
See What Campaign?
Play 100 Battle Mode Matches
Note that you don't have to win them, simply use the block re-arranger to destroy your first block and end the round in a matter of seconds.
This is one of those trophies that will happen without you really trying. However, if you are having trouble with this, play the beach level.
Beat 100 demon cavalry
Similar to Grubby, you will get this without really trying. If you are having trouble, the volcano level is a good place to go.
Win a match using beverage mode controls
This is extremely easy, especially if you have a second controller, just set it up and win the match using beverage mode. If you don't set it up so that your team has 2 expert CPs against a very easy CP.
Slam Bolt Royalty
Beat all the hidden campaign levels
As of March 30th 2011, no one is known to have this trophy, it could be glitched. I personally can not find the hidden campaign levels.
Steal your way to victory
This one unfortunately requires mostly luck. Whenever you see a purple ninja, try your best to get it. It will allow you to steal the enemy's blocks. Now the only thing you have to do is hope that they only have one block left for you to steal.
Beat Mountain Top 1 without taking any damage
This is not as hard as it sounds. your blocks can take damage, your character can't. Just familiarize yourself with the boss' attack patterns and aviod everything he throws at you. I also recommend playing on casual for this trophy.
Creep Rights Activist
Win a level without killing any baddies
This is extremely easy, especially if you have a second controller, just set it up and send one player to the corner than don't touch the controller again. If you don't set it up so that your team has 2 expert CPs against a very easy CP and let your CPs do all of the work for you.
Beat all campaign levels on expert difficulty
This is very difficult. The developers put in the expert difficulty so that the game would be challenging to them. This will require a lot of practice and a lot of time to familiarize yourself with all of the aspects of the game. Every level will take a number of tries to complete.