Looking good.
looks like you phoned in the body a bit, not saying what you have doesn't do the job, but for accuracy, it looks like the body has an elevation all around the outside, where you just have a big extrude in the front and some little boxes and things along the edge. (don't know if that explained it, hard to word, what i'm trying to say)
Are you trying to put several tanks together? There are a few parts that aren't on this reference:

Keep working on it though, hammering out the silhouette is the most important part, the details will help it out.