What is the ruling on purchasing virtual money in electronic games with real money, given the possibility of losing all of it in a single round, and is this considered gambling or usury? What is the Shariah evidence for that?

If the game is originally permissible, then buying its advantages, such as virtual money, is not forbidden, and this is not usury or gambling. The problem arises if the game falls under the category of gambling (qimar) or Maysir if losing in it entails the player losing the entire amount and their opponent winning it, for all gambling (qimar) is Maysir and is forbidden.