At early levels the enemies have little, or no, armor or other defense boosts. As you progress that changes, and which item to use on each enemy matters more. Similarly, healing is not as important early on as you should be able to easily beat most low level enemies. The difficulty ramps up around level 10, with a story event. We will redo the early difficulty for the final game, but for now want the start to be easier to allow testers to easily see more of the game and experiment.
We do have a plan to add some additional variety to the items by having equipment be less about direct attacks and instead affect your stats. For example, the more armor you eat the higher your defense will be. Each Slime also has their own affinities, and some will get better boosts from certain items. This has not been implemented yet, as it is going to need a lot of balancing to work well. We plan to introduce a hunger/fullness concept with it to help deal with the potential for getting into an easy fight and just mass eating a bunch of stat boosting items. The concept is being fleshed out as we work on other things and is planned to be added after a few more features we think need to be done first.
There is also a plan to allow the Slimes to have limited equipable items later in the game.
Status effects like stun are on the list of things we are debating. We are thinking of adding a few, but also want to balance things so combat moves quickly, and things like poison or regen would not feel as useful if the combat ends before they have any effect.
Thanks for playing, and the feedback!