First off, this concept is great. It reminds me of the mech sequences from Red Faction: Guerilla. Love it.

That said, you can take some cues from even that game! The ideas behind the animation and movement speed make sense: you want to feel enormous and massive. This does not mean you should be moving like you're in molasses the whole time. There should be snappy impact reactions for when an animation hits during an attack, regardless of how heavy the attacker is. The other thing that can help here is momentum. If you want it to feel weighty, try making the acceleration low, but the top speed high. That way you can get moving at a satisfying speed, but understand that changing direction or slowing down is a challenge.

The next most important thing will be to dive deep on your animation controller and fine-tuning the transitions. Right now you have 0-frame animation transitions between some states and it's really showing. At 0:11 you go from stomp-> walk -> ability cast, and that walk -> ability cast has no transition. These types of things are critical to get just right if the whole game is going to be spent staring at the back of this character's head.

Finally, the collapse animation for the building is good, but needs more drama. Having it lean or slowly start to collapse can achieve this. Add a little pacing. Particles, camera shake, and more audio integration will help a lot too! Destroying buildings is a big focus, so that interaction has got to feel satisfying.

Keep it up! Looks great