Just a note, builds that are small signs with words on them aren't really considered when taking an app into consideration. They usually don't take much time to make at all.
Also, builder rank usually requires builds that have some nice detail, complexity, or both. Sprites are generally ok as long as they're not small and simple to make. While we do look for builds to have a certain amount of hours played, it's mainly just a prerequisite to getting the rank. Ranks are mostly based off of the builds made. If you want, I can provide you with some ideas for complex and detailed builds. =)
Your latest build seems pretty neat, but I can only see one out of 4 images. Any chance you can re-upload the first three?