Here is another instructable.
This was a Lego project I did not to long ago.
It's really simple and easy to build.
Lets get to it!
Step 1: The Body.
Just so everyone knows... the pictures do most of the talking. I will try to explain as much as I can.
So the body is made up of 2 white circle dishes, 1 black 1x1 brick with studs all around it, 1 bar, 1 1x1 spike stud,
2 transparent studs, 1 1x1 stud with clip, 1 1x1 brick with 2 studs on the sides, 1 white cone, 1 3 bar piece, 1 flashlight sort of piece, and 1 technic 1x1 push in stud.
If you have any questions, comment below.
Step 2: The Arms.
The arms are simple enough.
You need 4 wrenches, 2 droid arms and 2 special bar/wrench/stud piece.
Then assemble them like so in the pictures.
Step 3: The Legs and Finshing the Robot.
The legs are made out of 2 bendy plates, 2 transparent 1x1 slopes, and 4 grill 2x2 plates.
Then, assemble like shown.
Now the robot is finished!
Time for some weapons!
Step 4: Weapons
Now you need:
1 gun like piece, 1 chainsaw, 1 robot arm, 1 loud speaker, 1 white cone and 1 red transparent cone.
Then you also need a 2 hole bar piece, 2 flick missiles, 2 transparent orange studs, and 1 clip piece.
Then assemble like so.
Step 5: Weapons (continued)
Now for a sniper rifle and a harpoon.
Get a long gun piece, a 1x2 clip plate, a 1x1 stud with hole piece, a red transparent 1x1 slope, and a black head.
Also get a harpoon and a robot arm.
Step 6: Finished!
And tada! You now have a Lego Battle Mech that you can switch out weapons with!
Now go blast those aliens!