When I saw the time machine, the film lost its magic for me. Everything up to that point (just about all of which I loved) suggested it was a film that wouldn't show it.
The ending is way too tidy for a film so loose and free up to that point. I'm all for toying with expectations, but you almost need a predictable rom-com version of the script with far less skilled leads for this ending to line up. That's how incongruous it felt to me in relation to the rest of the film.