Y'could try playing a bit w/ composition, say by using the rule of third or, as said before before me, the golden ratio (tho' Iunno if y'wanna change your 500*500).
Try rotating the background a bit, y'could find a sweet spot.
I'm thinking that ship and its fire could pop out of Mars a bit more, maybe by making Mars less saturated or darker, if not shift the hue a bit.
...That's Mars, right?
Also, yeah, the text's kinda too futuristic for this aesthetic.
I like how it's clean tho', good job on that