Assuming Beckett's work would be made into a film, one could see some significant differences. The feel of the play as one that is disjointed and reflective of the lack of coherency in the modern setting could be lost in a film, which enjoys the opportunity to engage in stylistic unity and perfection. This would go against the spirit of the work. The fact that close ups and potential angles can be chosen would belie Beckett's belief that our choices do not necessarily alleviate our condition of waiting, and that the transcendent force which can select point of view and create something more aesthetically pleasing is not present. I think that the very nature of a play helps to convey much in way of Beckett's meaning and this could be lost in translation to film.
The great Ingmer Bergman wanted to film Waiting for Godot but Beckett did not allow him as he felt the film will become too Bergmanesque and least Beckettian at the same time. Beckett valued his authorial signature and was very strict when it came to taking liberties with the performance of his work.
The recent Beckett on Film project filmed all his stage plays from Godot to What Where. I liked the shorter plays much more than the longer ones.
Godot was directed by Michael Lindsay-Hogg. Barry McGovern, an old Beckett-actor played Vladimir while Estragon was played by another Beckett-vetaren Johny Murphy. Stephen Brennan played Lucky in the film.
The film was absolutely faithful to the play-text and Beckett's stage-directions. As for the different impact, the medium will bring in its own effect. But the film was made primarily in a theatrical mode. The limited visual frame was problematic because it failed to underscore the spatial idea of infinity in the text. The acting was up to the mark and Beckett's insistence on toneless rendering was adhered to.
The 2001 Lindsay-Hogg production follows a different performance text to Beckett's original French version or English translation, and is based on the German production directed by Beckett in 1975.
Differences include changing the 'mound' in the set to a 'stone', which is later specifically mentioned by Vladimir.