Completing some of these seems impossible if you don't have a high tier.
thats the thing, they pretty much are. The heavy tank 15 mission needing you to get 8k damage is next to impossible on anything less then a tier 8, where as if i would have had a tier 9 or 10 heavy, i would have completed the mission no problem. It took me 3 days, i had to grind through the kv-3 line and finally get the top turret on a kv-4 before i completed the mission in a tier 9 game. I accrued 6k blocked damage, plus my 1600 health and i scored 2500 damage.
The light tank missions were all the same as the heavy, you absolutely needed a high enough light tank to guarantee you access to high tier matches, it was the only way to very easily get the necessary damage. Without them, its just up to you having a extremely good game, which doesnt come too often, since you need both your team to suck, and their team to suck enough for either side to not get too big of an advantage and roll the other.
Ive finally completed the Stug 4 missions, i completed with honors all the the missions with the exception of the spg line, of which i am actually doing now so that i can get the last girl crew member. Im stuck currently on damaging two vehicles with one shell, which is again, just one of those missions that is absolute luck and not something normally done in a standard battle, especially not in a shitty german artillery with no splash.
If people dont know this already, the missions get increasingly harder. All the stug missions allowed tier 4 vehicles, and had specific damage or spotting numbers you had to achieve. The t28 concept missions require tier 5 or higher, and the numbers have basically increased on damage required by around 2k roughly, so good luck lol. I honestly dont expect to see many t28 concepts, nor even the t-55, and the ones you will see with them will be all the rather good players.
