Great job on the game. The instructions are well done, and I like that I had to survey the level to plan out how I wanted to approach it. There were even a couple of times where it felt like I had options, which was interesting as I weighed them. I love the flat eyes of the player sprite. It looks so menacing, like he's just looking for a reason to blow up. :)
There's a small design issue that is sort of inherent with your take on the theme, that being at one of the levels I wanted to blow up two workers at the same time, so I had to wait for them to both be in my blast radius, but it seemed like as one would enter, the other would leave, but it varied each time so I had to wait for several passes of this until it felt close enough to attempt.
Since the workers can rebuild your walls, it would be nice if they left rubble behind so that I can keep track of where the walls were previously after I blow them up. It was never an issue, I just think it'd be a nice feature.