While it's hard to communicate this in the demo at this point, the game is going to be VERY puzzle oriented when it comes to the dungeons, and the puzzle complexity really comes from the different item combinations you'll encounter through the game.
Each of your 10 items, will be able to be used in 5 different ways (it's own single purpose, and then 4 different ways depending on what item you equip with it. Resulting in 50 different item combinations!). Unlike other Adventure games, you can absolutely swap out your main attack weapon, and equip something else if you prefer another item over your cardboard sword! And, in order to defeat some enemies, you'll have to!
For instance, if you equip your Snow Globe, it will simply give you a bubble that then protects you from damage until the shield breaks. However, if you equip the Snow Globe with your Axe at the same time, it will then create a shield of 3 spinning axes that spin around you and follow you around the screen! This will interact with puzzles differently than if the axe was used on it's own and you can also use it to defeat enemies!
In a lot of Adventure games, there's items that you don't use a lot, or that get used later on with no real new mechanics to speak of. This makes the item itself less interesting because you know exactly what you need to do with it. You simply open your menu, equip it, use it and move along. I wanted to avoid this.
So each of your items will have their own purpose, and gain new abilities as you find new items that are able to be used with it! Also, because you can decide which item to put on either O or P, you can slightly adjust how you play the game, to what feels better for you!