TACTICS
GENERAL TACTICS.
ADT is a MUCH faster-paced game than original myth. the units move faster, the projectiles fly faster, the weapons are more powerful resulting in quicker fatalities and the maps offer plenty of ambush possibilities. You must keep your wits about you at all times if you do not wish to be swiftly anhiated by a well-executed offensive move.
Micromanagement of troops is also essential. although you cant be everywhere at once, try not to just assign a squad of units to a target and leave them to it. watch them, keep them selected and be ready to react to anything that may happen to thwart your plans.
NEVER bunch your troops together. hammergunners are always on the lookout to save ammunition and if the bastards can get 10 men in a single salvo they'll be the toast of the platoon for months.
WATCH OUT FOR TERRAIN HEIGHTS - sometimes a marine will not be able to shoot at a target due to undulations in the trerrain. make sure he has a clear shot. THIS IS ESPECIALLY IMPORTANT FOR GRENADES!!!!!!!! because if youre shooting a grenade at a target 50 yards away, and there's a small grassy knoll at your feet, the grenade will detonate on the knolll... and at your feet.
SINGLE ALIENS DIE QUICKLY! a problem shared is a problem halved, so share a squad of marines between say, 16 aliens, and watch the aliens half the marines.
MARINE TACTICS
Marines can lay down a withering hail of fire but take a short time to reload between bursts - only attack if you're sure of a stopping shot. this applies especially to smartgunners since the smartgun will overheat after three or four bursts and take a considerable amount of time to cool - longer than the life expectancy of it's owner in many situations.
Smartgunners' DU rounds will go right though a target, so see how many you can line up and knock down with a single round!
Grenades used with precision can be devastating, but can also decimate your own troops if you inadvertantly fire them into a nearby wall or object. flamethrowers are unfortunately prone to catching fire to te ground directly in front of a unit, and best results with both weapons can be achieved from a higher vantage point.
Hammergunners are best kept at arms reach from the enemy due to their long range and ballistic trajectory (firing a salvo over the walls in Northwest Outpost is a favourite of mine).
Autoguns are an excellent defensive weapon and even when out of ammo they will deter an enemy from approaching them.
Powerloaders can withstand an awful lot of punishment. try sending one down a heavily guarded corridor and bring your troops up behind it - a shielding tactic.
ALIEN TACTICS
Your Drones and their bigger cousins the Praetorians can move fast and take a fair amount of damage - mob tactis work well here, overwhelming the enemy and cutting them to shreds. you will also find great psychological advantage in a mass rush of aliens - nobody wants to stand around and argue with them.
Aliens, praetorians and queens can pick up things and chuck them like ghols. try caniballising a few of your own aliens and load up your remaining alien mob with those lovely acidic grenades. (smaller body parts can be thrown further)
Facehuggers used in conjunction with the Drone mobs can also have a hugeley effective "panic" effect - they are small and creepy and sending them in before your main force can confuse and disorder an enemy formation quite successfully, allowing you to walk in and mop up with your heavier forces.
Aerial drones can spit acid quite a ways, and although they make excellent targets for enemy small arms fire it is nearly impossible to hit them with grenades and explosives. again, large formations work better and can quickly decimate enemy forces. the aerial drone's speed and all-terrain passability allows for devastating hit and run tactics, allowing you to harrass an enemy and drive them from any hiding place.
Queens are ultimate badasses, and although slower than most of your alien forces she can still outpace any human and absorb an awful lot of punishment into the bargain. the sheer panic that a charging queen will provoke can be enough to rout an enemy from his position.