I like the original plan, starting with the plain and progressing into a more realistic style. Like Portal 2, starting with overgrown and progressing to a fixed aperture.
This way, you could even add a story line to it, if you wanted. A changing art style could be translated to improving testing software or something. The labs get more realistic, in addition to more testing mechanics. Could be cool.
streak1
joined
This member has provided no bio about themself...