During the Active Time Report Page 4.0 broadcast, Game Director Hajime Tabata gave quite a lot of information about the Episode Duscae demo, which will be released on March 17th alongside Type-0 HD. 

• Having Noctis warp around, block and evade costs MP.
• You can select weapon abilities with the D-pad.
• The title screen changes according to real world time between day and night.
• Noctis can't go very far into the water in the demo, but he will be able to go further in the final game.
• The AI reacts according to Noctis' movements. When he changes speed, his party will too. They also react automatically to the situation.
• A red "Encounter Gauge" appears when enemies are close, and battle starts. At that point the marker disappears.
• Not all monsters are hostile, but they will defend themselves if attacked.
• Depleting MP when Noctis dodges is shown by a  blue effect.
• Enemies will come in a wide variety of sizes.
• When you camp your party grows closer, making new party attacks available.
• "Rush" weapons can unleash continuous attacks.
• You can change weapons while in battle via the menu.
• Yellow markers indicate a quest's destination.
• One of the big bosses in the demo is "Behemoth Smoke Eye." You can find his footprints, giving clues to his location.
• The demo's main goal is to gather money to get Noctis' car fixed. Killing Behemoth gives a large monetary reward.
• Companions will call Noctis over when they see an interesting spot.
• It's more dangerous at night than during the day.
• Poison is indicated by a red effect.
• Food cooked by Ignis at camping spots gives beneficial effects. They include focus and speed bonuses.
• After you receive your buffs, you can level up if you earned enough experience.
• You can fast travel between camping spots.
• If you move to higher ground, you can be safer from enemies without ranged attacks and earn yourself some time to regain MP.
• When your HP reaches zero, you don't die immediately. You can be healed by your partners before the red gauge runs out. If it does run out, Noctis dies.
• The demo won't run at full 1080p/30FPS, but that remains the target for the full game.
• The map of the full game is 10-20 times bigger than that of the demo.
• The demo will not have the weather system implemented. That's because weather effects won't be completed in time. Those effects will include wet grass that will dry up when the rain stops.
• Noctis has his phantom sword in the demo. The number of swords will vary, and they will surround the character. There will also be normal weapons. You have to actually find the phantom swords during gameplay.
• Party attacks are really powerful, but there aren't many in the demo, as they're based on party progression.
• When you finish the main story of the demo, that's not the end. There are more tasks unlocked afterwards, and you can continue looking for phantom swords.
• Data won't transfer to the final version, but your save data might have an effect in the complete game.
• Adamantoise won't appear in the demo. It will be in the full game.
• The ending of the demo will include story elements.
• The game itself is 60% complete now. Some elements are further along than others.
• Next week there will be another presentation from London.

The information above is courtesy of Twitter users SQEX☆GAL and Doki Doki Nii-chan, who are evidently much better than I am at translating quickly from Japanese. If you want to see the absolutely spectacular gameplay showcased today, you can find it here.