So I saw the press "E" thing to rewind the environment, did the land fall or something? Also, I didn't notice anything when I pressed "T", not sure if I was missing anything. Maybe some sort of animation by pressing "T" like you did when he holds the hourglass would be nice.
The design of the guy and the agent were pretty solid I think, but adding things in the background and putting more detail in the tiles, especially the dirt part below the grass, would be a benefit to you. More challenges besides just the agents and the hourglass could be cool. Also, the agent seems to float to other tiles to get to you, not sure if this is intentional but if it is you should add a particle effect to his movement, since at the moment the way he moves looks like a bug.
However, the concept and gameplay behind your game is solid, and I liked it. The only thing it requires is small tweaks. Good job!