This was the first version of the game I've played, so I can't compare about the progress, but I'd want to share a few thoughts.
I've plated the gauntlet mode the most (since it has a male model implemented) and even though the idea is simple it's also really fun. I did have a hard time maneuvering around cars though, I got stuck when I got too close to any of them. Especially the ones that were already flattened gave me some hard time - it'd be nice to be able to be able move over those. Personally I think it'd be cool if the giant strolling around the gauntlet lane had some more actions like, for example, stopping for a moment and looking around, taking a step to the side and back to the lane, occasionally making a bigger steps/jumps. Just some simple stuff to add more variety :) It would be also helpful if the restart option got you back in action instantly, without returning to the model choice option.
I've tried the race mode too, but the car's response seemed too wild for me! My car spun and I've kept loosing the sense of direction I'm supposed to be going @_@ A map or 'wrong direction' display would help. Including some AIs riding alongside might be interesting too. Also I didn't have much luck with bumping into the giant ladies, it seemed they had something more interesting to do in the other part of the map xD
I really liked the highway level o_o Even though giantesses are not my thing the general air of danger, figures lurking ominously in the darkness and death coming from above made this a pretty intense experience. This part of the game seemed pretty polished and fun to play.
As for giant's behavior throughout the game I liked the booming sound of their footsteps, it builds the immersion. I think it would seem even more impactful if screen-shakes were added, with their intensity increasing as the giants move closer, maybe even making the character jump a little as a foot lands nearby. I also think it would be cool if they turned their heads to follow the players movement, so we'd feel that we're being watched as we traverse the dangerous terrain. In daylight mode adding shadows might look cool, but I'm not sure if this wouldn't cost too much computational power to render.
All the ideas above should be taken with a grain of salt, as the game is in an early-alpha and some things just can't be expected of it at this stage. Playing it as is now is still a lot of fun ^_^ Thank you for your hard work!