Word meaning "to begin simple but to become complex"

I'm looking for the word(s) that describes my current dilemma:

I have begun a project that seemed, at its outset, quite simple - tedious, but simple. However, the further I get into the project, the more complex it becomes; the longer I work on it, the less likely it seems I will complete it.

Is there a word or idea that describes this? It's like running at a speed of 10 miles per hour after something that is moving at 11.

Solution 1:

How about 'snowballing complexity'.

Solution 2:

If you're willing to accept an idiom, you might try spiral out of control.

"The project started off easy, but quickly spiraled out of my control."

Or you could possibly use the word exponentially to convey your meaning.

"The project started off easy, but grew exponentially harder as the work progressed."

Solution 3:

If the project became complex because you decided you needed do more than you originally intended then consider scope creep.

Scope creep can apply to projects that weren’t necessarily simple to begin with, but definitely does mean that they have become much more complex than originally envisioned. In this case, the emphasis is less on “things were more complex than we gave them credit for,” and more on “no one seems to know when to cut off new ideas.”

From Wikipedia:

Scope creep (also called requirement creep, function creep and feature creep) in project management refers to uncontrolled changes or continuous growth in a project’s scope. This can occur when the scope of a project is not properly defined, documented, or controlled. It is generally considered harmful.

Solution 4:

If you're looking for a single word, complexify [M-W] fits the bill:

My proposal would simplify the process, whereas yours would needlessly complexify it.