The wheel's looking better! Consider adding some hints of treads in the light/shadow boundary on the wheel to make the rotation more clear, perhaps? Jittering the shadow is a good solution for when you don't have room for adding actual animation, but you do have room.
T added animation of the head flying in the distance is a great touch!
I feel the up arrow and added delay between the checkbox and lift-off is an unnecessary delay, it just makes the countdown feel like it fizzles out, rather than like a lead-in into the launch.
The spring and face shaking is a nice effect, but it feels unconnected to the launch because the head stops shaking for a moment before the actual launch. Have those animations overlap, so that they feel like parts of a single action.
The antenna on the robot's head has a nice bit of drag on it, but it the framerate/smoothness there seems lower than in other parts of the animation.
The launch motion of the head still looks rather boring to me.
I probably should've brought this up earlier, but is your goal to simulate a spring-launch (which would be super-fast at the start and then slow down), or a slow rocket launch that speeds up (but which, comically, is achieved via a spring)? I gave feedback with the assumption that you're going for a rocket-like launch since that's how you animated it in the beginning. If you want to really sell the spring launch though, then instead of starting slow and speeding up, start fast, perhaps so fast that you'd need a smear. Since you're now showing the head entering back into the frame in the distance, you have the luxury of the launch reading clearly even if the viewer can't get a good look at the launch itself because it's so fast.
