Q: When playing Solonauts, does the game end when I can no longer refresh to a full five cards, or can I play out the rest of my hand?

A: Since you don’t really have turns in when playing solo, and your hand size is mutable, I can’t think of any reason the game would end before you’d won or lost it (i.e. when you can no longer draw). Keep playing until the last usable card in your hand. You’ll probably need it.