Initially nothing worked. It wasn't until I downloaded offline maps that suddenly it started working.
Text is too small to read. If you are using this for navigation it has to be readable at a glance. In particular the bar along the bottom, both numbers and text, is too small.
There is not sufficient contrast on the cycletravel map between features and the background. The Wayfarer map is better.
An example of a display that can be read is the OsmAnd app, which you recommend for opening gpx files.
The display does not zoom in as you approach a turning.
Double tap to zoom in does not work.
If you go off route it doesn't recalculate to get you back on track, or better still give you the best route to your destination from where you are now. It just hoots and then does nothing.
The display does not switch to night colours after sunset.
Having said all that, I like the interface for designing a route, and the auto start.
The routes cycletravel comes up with seem more sensible than other apps.
I like the blanking of the screen between turns.
I appreciate the app is new to android (I am running android 14 on a Samsung S21+) and that things will change.
I will continue to use the Web version of cycletravel to design routes, but until I can see what it is telling me I think I will have to navigate with something else.