When you have remote explosives, do not use up ammo for your other weapons. It only takes one to a few remote explosives to take out enemies. When you start the game and get to the part where you see the four troopers and the enemy APC, throw a bomb down by the APC. Detonate it and the bomb will blow a huge hole in the ground. If done correctly, the APC will fall in and explode when it hits bottom. Take advantage of the geo-modification of this game. This also works with groups of enemy soldiers.