Slow and expensive, but boasting massive amounts of offensive and defensive power, Mega Tanks are the ultimate in ground-based firepower.
The Mega Tank is a unit that deals in extremes. Its cannon is capable of completely obliterating any Land-Based unit in one shot, save for other Mega Tanks. They will need to be close to full HP to do this to Md. Tanks and Neotanks. Against lighter-armored Ground units, Mega Tanks can still destroy whole units when they are at 6 or 7 HP, depending on terrain. Their Machine Guns are very effective against foot soldiers as well, but using Mega Tanks to combat infantry is extreme overkill. Their Machine Guns are also no more effective against Copter units than a Neotank's, so using them to attack copters is inadvisable. This firepower comes at the price of low ammo capacity, however. With only 3 shots before needing to resupply, a Mega Tank can easily run out of ammo if not careful, losing a ton of firepower in the process. Keeping it near Cities or APCs can help alleviate this problem.
Similarly to its raw offensive power, a Mega Tank has sky-high defense, taking low to middling damage from any other unit, save for other Mega Tanks. As a result of its heavy armor, the Mega Tank is also a very slow unit, usually being the slowest ground vehicle and taking a considerable amount of time to reach the front lines. Generally, due to their very high cost and general ease of outmaneuvering, Mega Tanks are only commonly used on maps or settings that generally lead to players acquiring very high amounts of Funds.
Mega Tanks are extremely powerful units, taking quite a few units firing upon it in unison just to be able to take it down. Mega Tanks take very low damage from Indirect Units, but still cannot retaliate against them, so they can prove useful in whittling it down to a more manageable state. Attacking it with other Land units is not recommended, as they will only do light damage to the Mega Tank, taking high damage from its counterattack. Air units are generally good for fighting Mega Tanks, as they are still defenseless against Bombers and Stealths. B-Copters can be cost efficient at fighting Mega Tanks as well, being able to take a few hits from them, and being significantly cheaper.
Overall, the best tactic against Mega Tanks is to use its very slow speed against it. Being slow units, Mega Tanks are very poor at picking optimal engagements, instead just opting to throw its high stats around to compensate for this particular weakness. Forcing engagements in areas that the Mega Tank cannot reach quickly will allow you to take out its supporting units before the Mega Tank itself can pose a threat. Without units to support it, a Mega Tank is a fairly easy, if very sturdy, unit to eventually overwhelm.