It's new feature day! The bad news first: this is a save-breaking change (as indicated by the major version bump), but I think you'll find it worth the loss, as we're now rolling out a node-base tower navigation system. After the first few floors, every floor will have three chambers. You'll be given multiple exits in the level and choosing one will determine which chamber you enter next. You can learn more about what you're in for by looking at the map. Hover over the icons and you'll see additional detail. You can also hover over the exits themselves in-game for more information.
If you move along the left or right chambers, your choices for the next level will be limited to only what's adjacent to them. Moving down the middle will ensure you always have the most choices for the next one. The chambers will often have a special theme for their store, such as showing cards mostly from a certain clan, or having gems, spells, or even relics for sale. You might also get bonuses in the level itself: coins, power-up items, or even an additional chest.
Happy escaping!