Just some quick feedback: when clicking the top right "x" to close the window, the options "abandon" and "continue" are maybe a little ambiguous: me being me I just saw "continue" and thought: oh that means continue with the abandoning, I'll click the other option. But that's the wrong way around.
So maybe "abandon" could be in red text, and the other option could be "continue shift" or some in context words that clearly mean "this is NOT the option for abandoning". Also the "continue" being bordered and the abandon not being bordered or having some hover-over highlighting feels a little off to me (e.g. if you're deleting a repo on github, the red "delete repo" etc options are all bordered and emphasised just as much as other buttons). So it feels like that UI choice doesn't really align with / is the opposite to what I've learnt from other UIs.
anyway this is the most nitpicks of nitpicks and really doesn't matter much - the game looks great!