Brief rundown of what I've figured out in SS regarding the spells and such. This might help people get some enjoyment where they're struggling or something.
Each spell that you bring to battle (and you can bring six) acts either as a spell which you cast directly (like the healing seeds or the fists that punch up from the ground), a melee weapon which is equipped for a certain amount of time (ice sword, axe, elemental giant fists), or a projectile weapon which you ready and then fire with either the face button or the right trigger (the chakram things, mortars, and other such things). Each time you cast a spell or ready a melee weapon you consume a charge of the spell, and these charges are limited. If you completely deplete a spell then the item that you used to fuel that spell (the token you equipped on the arsenal screen) is destroyed completely and permanently, you don't get it back and you can't refill it for the duration of the stage. This is preceded by a message that you're about to run out of that spell and its icon on the UI will blink red. You can refill non-destroyed spells during a mission by finding special locations on a map to refill your sacrifices - these show up as upwardly-flowing white streams in minds-eye mode (down on the D-pad). They don't restore to full, just a few charges, and these are also limited. This resource-intensive approach to combat is where most of the tension comes from, making tough missions a battle of attrition rather than just health and damage. Also any non-destroyed spell items will be replenished to full after a mission, so if you're careful you shouldn't run out of spell items.
There are two ways to manage your spells (though they don't get unlocked until late in the demo): fusing and boosting. Boosting combines two (or perhaps more, later on) spell items of the same type to make one improved version, generally holding additional charges than the original version, this is pretty straightforward, and can be taken to higher levels. If you have four "sword of herpderp" you can combine them into two "sword of herpderp *" and then combine those into one "sword of herpderp **". Fusing is more complicated, but basically it allows you to create new spell types by fusing existing spells. Fusing the chakram with the ice shield gets you some sort of ice thorn projectile, for example. When fusing any boosted levels are lost, so you'll start back at the base number of charges for the spell.
Once you get past the laughably easy missions it becomes a matter of outfitting yourself with a variety of complementary spells, and alternating between attack styles so that your trips to replenish your spells will allow you to last the battle without breaking any of them. Elemental weaknesses are important, and fusing spells lets you create a variety of different spell types for each element. Given that this is just a small sampling of spells, I think that the system will be quite robust and engrossing later on in the game.
There are also a few other special systems. You can carve sigils into your arms which boost stats or create effects, you can equip one-time-use megaspells which sacrifice a body part for a massive boost, but carry penalties which will last to the end of the mission - and even into other missions if you don't treat your wounds. And, yes, some of the spells are cast with health which means that their number of charges isn't limited, they're only limited by your health pool.
Basically, the point of all this is that while at first it feels like you have a few strange and disparate attacks but all you really need to do is pull out your ice sword and slash away, you'll actually need to be smart about using different spell types once your training wheels are taken off.
Final note: I'm not trying to be condescending or tell anyone they ABSOLUTELY HAVE TO LIKE THE GAME AND IF YOU DON'T YOU'RE JUST STUPID. I'm just giving a quick rundown of stuff to maybe help people get a handle on things and see that perhaps there's more at work than they initially thought, and maybe give it a second look if they otherwise might not have.