Cool entry, very original and different to what I would expect from a Mech Game!
I really like the aesthetic, it feels coherent and it works very well for what you're going for. I think, however, that your game could use a bit of variety regarding the backgrounds. You could use the same assets you already have, but vary how you use them! For example, you could have a small bit be a forest, and then you enter a city, and you would have trees and buildings respectively. I think this might help the player feel like they're actually travelling since the world actually changes around them.
In terms of gameplay and fun factor, I'm not a big fan of clicker games, so maybe I'm not the correct audience, but I still think this is one that's pretty well made and it seems like the upgrades tie in nicely to your concept. If I'm not mistaken, you have two upgrades for your damage, one for your speed, and one for your passive money, right? If this is correct, my only suggestion would be to add some sort of visual feedback to the upgrades that affect your mech. The money one feels stronger as you upgrade it since you see so many more coins - doing something like this for the speed, like, for example, your "walk cycle" getting a bit faster, and the world moving faster as you upgrade it, would go a long way to making the progression in the clicker game feel more connected to the concept of the travelling Mech, and giving the player a stronger sense of progression and agency.
Audio-wise, I like the music you've chosen. I'm sad that I couldn't get to hear the voice acting you mentioned in your description, since I feel like it could've helped greatly to give me something to latch on to while I clicked away to buy more upgrades.
Overall, cool entry, with a very original concept. I'd love to see a version with the voice acting and a bit more polish! Keep up the good work!