If you watched this not knowing the plot or title...
If this was called something else, wasn't a remake, and didn't have obvious shots of a fly buzzing round as he enters the pod, the experience of watching the film would be so interesting for its mystery.
I love the part of middle act where no one in the film really knows whats going on, but its clear that Seth is changing in subtle ways. That kind of "gets under your skin" subtlety (and not-so-subtlety) would be such good fun to absorb and try to figure out if you had no clue about the fly aspect. A bit like a Black Mirror episode.
Then, once the computer confirms the fly DNA, you're left to deduce what must have happened.
Its just such a simple, pure idea for a transformational horror film, that plays into so many undercurrent anxieties about people becoming influenced/manipulated/desperate/sold-out and changing for the worst.