You could make bunch of cool fighting scenes and then ruin them by making the player press a random button each time... oh wait, you said quick-time events are already planned? well... I don't think it can get any worse now
Unless you would do the same s*** as did Castlevania: Simons Quest, where you are constantly told if is it Day or night with a horribly slowly writing textbox and everytime you die you would loose all your possessions, oh and lots of the level stuff could be so cryptic that you would waste your whole life trying to figure it out and thinking that the game is just broken...
uh, and don't forget that the main character can't swim and will die on the slightest touch of water!
also you could include one of those levels where the edge of the screen is constantly moving and if it catches you, you die and start over.
and if possible and thematic, make a level where the character is moving automatically forward, and you have to jump and catch all the items or else you fail the level
and maybe make some "trap" tiles which look like everything else, and you will die if you touch it, but you don't know that until you actually die on it?
and if you intent to add projectile weapons, make it so you can only shoot one bullet/arrow until it disappears
and make it so if you are on a low health, there is this constant helpful high pitch beeping reminding you. Also the screen could be whole red and hard to look at, so it feels more real...
and all the monsters should respawn when off-screen so you can have a fun time killing them over and over again.
also add a lot of foreground details, like big trees and bushes that obstruct quarter of the screen so you feel like you are actually there?