Use a dfferent color for the skye than for the explosion. The explosion will come out better that way

Hey Elvis, The thing I notice the most is that every element in the composition is separate from all the others. The tank, guy, mountains, wall and sky all take up their own space. This flattens the composition and makes it look like nothing is relating to anything else. This is why we want to overlap the elements in our compositions so that it gives it depth. I did a quick diagram of your painting to show you what I mean. I hope it makes sense to you and is helpful :)