Wow, lovely! I'm not much of a pixel nazi so I don't mind the gradient, it's nice. Sky gradients pack in depth like nothing else. The unique (assuming this is all original; not based on something) and strong design is refreshing.
Before opening this I rectified "drill crew" with a breakdancing squad. Must be the negative influence from the worthless and raunchy 'Kicking it Old School' movie I just watched 3/4 of (why did I watch that?). So I expected some urban blah scene, but this is so much better, heightening the pleasant surprise I think.
I don't even mind the 2x zoom, I assume you intend your audience to see it in that mode, so why not. Onto something actually useful . . .
Your title implies the brave dude on the grassy knoll there is "against" the drill crew, there being a mutual enmity, yet he seems like more of a passive spectator, seeing them off as they leave. He's not attacking, he's not taunting, just standing there; no action, very static, and certainly not giving indication of being brave. I like his pet. And the drill crew is oblivious to him as they board their airship. Would really boost things if the two entities interacted somehow. Furthermore, they amost have matching outfits, all you need is to change the "brave dude's" colors for them to not seem like they're on the same "team", and brave dude is their captain overseeing them as they fall in; board the ship.
Loading ramp on airship needs to cast some shadow on the grassy ledge. It reminds me of an in-game sprite with no sense of grounding against the painted background behind.
Tree's branches could use some darker shading where they dissapear into the leaves, it's almost as if they're just dead branches located out in front of the trees foliage. Did you try an additional highlight color on the top of the canopy? I can't help but consider it a little flat, when the other scene's foliage acheives a much brighter highlight, - wouldn't take much.
Did you try AA to blend the outer edges of things into what's behind them, rather than bold selout and completely aliased edges? - Such as the lower darkest part of the trees leaves, you got at least two shades you could buffer with there. I can't tell if the extra smoothing would really help that much.
Way to go.