Goal: end with only the four aces. Remove a top card if another pile shows the same suit with a higher rank (Aces are highest). Move a top card to any empty pile. Deal when stuck — 4 more cards, one per pile.
You win Aces Up when only the four Aces are left on the table. Cards are dealt one to each of four piles, and you discard any top card that has a higher card of the same suit showing on another pile. Aces rank highest, so they can never be discarded.
Yes, Deal works whenever the stock has cards. Discarding first is usually better, because new cards cover the old ones.
Aces are the highest rank in Aces Up, so no card can ever be higher in the same suit.
Largely. Good use of empty piles wins some extra deals, but many deals cannot be won whatever you do.