Your worst problem were those pesky Jagers with those double uber-Panzerschrecks. If you'll allow me a little advice, in your place I'd try to get rid of them first (by snipers or focused fire) and also in the final assault on his base I'd send all your tanks (IS2+T-34*2) at once instead of sending them one by one. I think 3 tank cannons would be enough to finish off his Jagers, even if at a cost of one T-34. But Katyushas were also a nice move - it's great how they can break the opponent's morale by wiping his entire squads or leaving not more than 1-2 men in each.