I see "unlimited creativity" in that trailer, but in my experience, this type of game is usually very limited.
So, as a small benchmark, I will pose the followimg questions:
Can you replicate the scene from ALttP's desert dungeon, where you shoot a statue and the wall moves away to reveal a new path? In other words, can the map be altered during play outside of bombing walls?
Can you create bossfights with custom strategies and weaknesses? For example, can you place a monster and set it to be only vulnerable to arrows, or set it to become vulnerable to everything for 3,5 seconds when hit by bombs? Can you make monsters chase certain objects or eat them? Can you make a monster flee when the player charges a melee attack, or make it use a charge attack when the player takes a certain distance? Can you set phases for a bossfight with different behaviors?
How versatile are the appliances? Can you put a monster in a chest, and then have that monster drop a key when you beat it? Can you create a number of pressure plates or switches that unlock a door when used in the correct order, but drop enemies when used in the wrong order? Can you check if a chest has been opened or a monster killed when using a switch? Can you set a switch to play a different note every time you press it, and create piano-shaped pressure plates that open a door when you step on the note last played by the switch?
Is there a scripting function with the ability to do runtime checks, however simple it might be?
If the answer to the majority of these questions is "no", you might want to reconsider that advertising slogan.