Kalran: Tales of the four nations/Stark "Ayra"

"Gustav, ready to shatter!"

-A Gustav tank rolling out

Tactical analysis

 * Let them come: The Gustav tank is the hardest hitting MBT of it equivalents. And while its autocannon is effective against infantry and light vehicles its main weapon is its second turret carrying a heavy railcannon, which is raised high enough that it can even fire over vehicles, that can break apart any armor, and in the event it survives the blast tends to leave its crew reeling for another shot, or uses airburst round that rips apart light armor and infantry. But the recoil and power means it must be secure itself to the ground before firing, and its round isn't that effective against structure.
 * Break them: In the event they face against a lot of armor or infantry it can fire a specialized shell. Either a round that penetrated multiple vehicles or what amounts to a giant bomb.
 * Cannons charging: But all of this comes with a few weakness. The most noticeable one is that its armor and autocannon power is rather underwhelming while it takes a few precious seconds to set up its railcannon, and it also takes time for the cannon to charge up and has minimum range, though the latter is remedied by the autocannon which still fire. And, above all else, lacks any defense against air, relying on anti-air units to cover them
 * Keep firing: Veteran crew tends to disregard the proper charging procedure in favor of charging their railcannon, even when no enemy is sighted, at full power before keeping it just below risk of overload. Though dangerous to the inexperienced it drastically increases the railcannon fire rate and range. Alongside this the crew gains a new autocannon turret that features another autocannon and a co-axial HMG

Ace upgrade
Railcannon will now charge up, even when its not attacking, and increase range and rate of fire and gains a second autocannon and co-axial HMG.