Ladies and Gentlemen our next game is "Space Boat" which is a... boat... in space. If you will, a space boat. It features a boat, in space, boating around through space. You collect yellow shiny things and...
Sorry, I'm in a silly sleep-deprived mood.
So, as an endless runner this all works. You can move, it's all easy to get and play, you have a nice looping soundtrack... cool
So, what next? Add some sound effects so I get a "reward" when I collect a shiny thing....
Increase the difficulty more obviously as you go on.. less rocks at the start, more as you continue. faster rocks, bigger rocks... something like that maybe
Oh and star fields, there are not enough star fields in video games these days - this game could have one ;)