It's really hard to do good mecha, but you've done that here in a big way. I always liked machines that look like their inspired by softer, biological forms - that's what makes Masamune Shirow's "Appleseed" mecha so good. I really like this.
This is delightful. Which is a more pretentious adjective than I normally like to use, but it just felt like the right one. I suppose "hilarious" would have worked, but there's more going on here than just humor.
Something tells me that the back of the walker will be fine, but a certain filling station will be needing a new roof soon. For what it apparently costs to fill that monster up, I doubt they'll have trouble paying for it.
I love how you made a mediocre everyday task seem so awesome just because of the subject. This is so wonderful! The expression of boredom as he waits for the tank to fill up.. And yay, I love Corel Painter!