He's received some useful feedback in the comments here.
That's the whole agile/lean idea: get user feedback early rather than spending a ton of time polishing it in isolation.
More appropriately, one of the central pillars of agile is to be in a releasable state at the end of every sprint.
If you look at the feedback, it's mostly stuff like fonts, spacing, etc. I think it's quite acceptable for a developer to get user feedback about the interface on v0.5 of free software.