I like the environment of the flood Zombie Attack mod, just based upon your screenshot. And yes, there is less modding in using existing tags, whether they are from the HEK or from the tags Bungie made. Modding is not so much the combination of existing tags as it is the changing of tags. For me, it's more fun to use my own thematic concept to change a tag than it is to change an existing tag so that it fits my concept. That sounds like the same thing, so let me clarify with this example: when I import an HEK tag (made for Halo Custom Edition) and change it so that it is "corrected" for my theme, that is not as fun as using the original Bungie Halo tags and changing them to fit my theme. The reason for this is probably because I'm changing the result of an already-modded tag.
The more creative you are, the more inspiring your work becomes. However, what is the value of an interpretation of another person's work? Interpretations cannot be said to be accurate or true to another person's intent; it's difficult enough to convey meaning directly through combinations of words and personal experiences alone. Additionally, gaining honor for oneself is entirely deplorable. The goal is also not to have fun, but to express ideas in new ways. Now if the audience doesn't know how to notice and interpret your ideas, then you might as well be talking to a wall, for at least you can pretend that a wall is interested in what you have to say.

I'm just kidding. You tell the audience how to notice and experience your meaning.
Anyway, the contrast in the themes of your two mods is striking: the first is wandering around, the second is fighting to stay alive. Both seem to be single-player themes.
Either you are groping for answers, or you are asking God and listening to Jesus.