Good one! Some nail-biting action to start off a jam is always nice!
I liked the presentation a lot. The screen-space effects (like the wavy heat blur) were cool, and didn't make the graphics any less readable. Almost all the hazards were well telegraphed. "Almost", because in the heat of the action I mistook burning embers for gold a couple of times :) Same goes for sound effects and music. They were properly intense and fit the action perfectly.
As for the action- at first I thought the grid movement would be limiting, but it fit the fast paced action perfectly! Some of the hazards were a bit hard to dodge (the line of flames moving from both sides at once hit me every time), but I guess that's a skill issue.
I always love when games like this have online leaderboards, and you delivered. Only nitpick here is that it would be cool, to see my result without restarting the game.
Over all- I'll probably return to this one, just to place higher on the leaderboards (6300 points may be good for the first time, but I can do better). Great game! Keep it up :)