The Megalith II Experimental Megabot is an eight-legged Cybranminor experimental land unit. It's armed with dual laser beam cannons, a large molecular ripper cannon on top, and 4 rear-mounted light AA cannons. Megaliths are good with land units according to the game manual.
The Megalith is not powerful but has a high range (64) while the Fatboy II has a higher range (100). It is effectively a support unit. Thus, you should use your army units (and Cybranasaurus Rexes) to cover them while they attack the enemy army. Use landscape to get close to a Fatboy with your Megalith so the Fatboy can't fire at you. When you get closer to the Fatboy, the Megalith has a larger DPS rate and will win 1v1 battle vs a Fatboy.
It's generally best to let the Megalith choose its own targets as the lasers use independent targeting systems and will not obey attack orders.
The Megalith has a tendency to move to the front of assault groups, placing itself between the enemy and direct fire allies (which often causes them to do nothing). Micromanagement can help negate this issue. However this can be a tactical advantage, as your opponent must first destroy the Megaliths to harm any other units.
Lone Megaliths do not get very far in a battle, so build 2 or more for a better fighting chance. But if your opponent is using a rush tactic with basic land units (Loyalist, Rockhead), one Megalith is a more cost-effective way of defending your base, than PDs. When enemy moves closer to your Megalith, hide it behind your base (under shields) or behind some PDs (point defence). In 1-2 minutes your army of regular units will be bigger than your enemy's. By this time you will get a 2nd Megalith and it will be time to finish your enemy.
The Megalith appears to be best at destroying many standard units, as it rapidly eliminates three units at the time, from a longer range than a normal unit can dream of.
The Megalith's range is bigger than PDs range so you can destroy enemys defence pretty easy and without loses of units.
Excellent in groups of 4 or more against a land-based army assault. However, similar experimentals in equal numbers will overpower the Megaliths.
Although the AA cannons deal a fair amount of damage they are not very effective so either group with AA units or put them in groups to make them more effective.
Two Megaliths escorted by two Bomb Bouncers and two engineers can easily destroy enemy units and air units due to the Bomb Bouncer's Anti-Air pulse ability. This can even be used to take on 2 Universal Colossi at once, if done properly.
Maps like Corvana Chasm are great places for Megaliths as they have long range and are able to do area effect very well considering the small walkways to get to where you drop them off at.
It is also recommended to save Megaliths for large-scale attacks, as they require much support.
That said, Megaliths (like Fatboys and Urchinows) don't require a huge expenditure of research to unlock. Teching straight to the Megalith can be an effective early-ish-game strategy, especially if you have access to a reasonably large number of mass deposits. Build factories and enough Loyalists to cover them (or go and harass your opponent, either should work), and of course point defences. Your lack of unit upgrades puts you at a slight disadvantage early on, but once the first Megalith rolls off the assembly line, the balance tips the other way. As mentioned above, Megaliths make excellent defensive units. Once you have three or four of them, go on the attack. This works wonders against the AI; you should be able to rampage clear through the enemy base this way. Another, similar strategy that can be effective is to tech to the shield generator and mass conversion ability first, then build several experimental factories and send teams of three or four to attack your opponent(s) from multiple directions. I recommend researching Adaptors once the Megaliths are acquired, as they conveniently patch all of the Megaliths' weaknesses (non-stellar AA, slow movement and large size implies vulnerability to missiles, being fire magnets that like to stand in front of the rest of your army).
Megaliths' range is long enough that they can blow up Commanders and avoid the explosion radius. Use this to your advantage when making base runs. Killing the ACU from outside the nuke radius takes out a lot of the base for you very quickly, to little disadvantage, especially as the rest of your army will typically be hiding behind the Megaliths.
A good strategy is to get an early land factory or two, get adaptor tech, and rush to Megaliths and build those 2 units throughout the game. With the Range, Damage, and health of the Megalith II and the adaptor shield, anti missile, and Anti Air, its a very potent combination.
The Megalith II seems to be a combination of the old Monkeylord and (original) Megalith. The Monkeylord was among the easiest-to-build experimentals in the game, and took the form of a huge, six-legged amphibous machine with electron cannons, SAM missiles and a microwave laser. It had 65000 health and was well known as an all-purpose assault unit. The Megalith made a dramatic appearance in campaign when Dr. Brackman marched it to QAI's base (QAI was a Seraphim Quantum Artificial Intelligence rehabilitated by Brackman, who it later betrayed) and destroyed his server core using a custom electricon cannon. In typical use, it stood tall enough in the water to engage battleships, had a health count of 110000, twin proton cannons, a flak gun, torpedo launchers, and factory capabilities, with a role not too different from the original Fatboy. The new Fatboy and Megalith have traded their factory abilities, higher damage capabilities, health and amphibious qualities in favor of availability and lower cost.