When the battle starts, use the Flechette's alternate fire. The little electric drones will follow him around the room. Also they will keep his shield down, and, if you use more then one set of the drones, as an added bonus, they will take out all the little buddies the General calls to help. Then while the drones are out there hit him with the alternate fire of the shotgun, and set electro-mines around where he appears at. The drones will follow him no matter what, so it won't be to hard to follow his movements. Doing this the General will go down fast.
Defeat the Crazy General
The most effective technique is to slow down time and hit him with a full railgun shot; the alternate fire of the railgun; or the alternate fire of the shotgun. However, you must first disable his shield with an EMP grenade. Once done, you will do substantial damage. It will break into a intermission sequence and spiderbots will appear. Kill themm then resume fighting the general. If you have enough Bio Energy, repeat the previous tactic. If not, use the EMP, then the alternate fire of the railgun or shotgun. The shotgun is easier to hit him with, but does less damage. After you inflict more damage, walkers will appear. Destroy them with the method of your choosing (rocket launcher recommended). Then, once again resume the fight with the general. This is his last round, spare no expense. Wear down or use an EMP on his shield, then kill him with massive fire power, or one of the alternate attacks of the railgun or shotgun.
Easy kills
Enemies that are not Bosses can be killed with the ice pick. One hit and they are down. After about a second you hear the sound of the ice pick breaking their spine.
How to control spiderbots
To control spiderbots, shoot them with the icepick.
Kicker at level 02
After you come out of the armoury and have your carbine and pistol, you will walk past a soldier, he will say permission to open armoury sir! walk over to him and press square, once you have done this follow him till he unlocks a door. go in, you should be in the armoury, if you look around you will get lots of grenades and some other stuff, if you look carefully you should find a sort of gun lying on the floor pick it up, this is the kicker, a tele-kinetic gun.
Turn off alarms
You can use the Gravity Gun to turn off alarms from far off. If you get seen and the alarm goes off, just point it towards the red square and push it forward. This will save you time dealing with the NPCs. This is especially helpful when dealing with the invisible guys.