Cool!
It all pretty much looks good - yes, a little polish on steel wheels and tracks, and a little fading and scorching of paint on those heat-shields, the "lacking" hoist cable and hook, and, yes, this thing should have some zimm on the original Tiger chassis parts - all the other's notes I second. But it's a nice effort and good-looking build, and Be Proud!
The one thing which hasn't been mentioned yet that "really" disturbs me (OK, just a tiny amount!)... the very sooty muzzle! This weapon probably never got fired more than a few times (huge rounds with little supply, slow firing rates, short vehicle life-spans, etc.), so there would have been little opportunity for any sooting - that and this weapon had a rather special design whereby the barrel was actually vented forward (those small holes around the muzzle allowed chamber gases to blast forward as the projectile "left the building"). This would further reduce the muzzle-blast and likely sooting. I would suggest that only the muzzle face should have much soot on it. Just my opinion, of course!
Great job!
Bob