I'm using Google Translate to write this, so the writing might get confusing for you.
Well I have some suggestions to put in the store and also in the game and the first suggestion is to put other types of sword or if you can make other weapons to sell in the store (ex: axes, sledgehammers, bow and arrow and other weapons of your choice) I also have a suggestion to create flying enemies (to make the bow more usable in the game) and to leave the game with a greater variety of enemies for you to create, also add to the store some "concept arts" of the game that can only be unlocked with x value to make the replayability more worthwhile and finally and which can be very complicated is to add in the store other types of attacks or spells for the player to have more options when fighting such as dash, double jump (or triple), throwing daggers or knives for longer combat and spells that could have a system in which each enemy would suffer with crit depending on the element cast but anyway this last one is very complicated so that's why I left it last. Good luck and may you be able to progress your game a lot.
(ps: I forgot to also mention about the Unity translator that so as not to have too many problems for other players if you add this plugin it translates automatically into several other languages and is a hand in hand until someone makes himself available to make a human translation of the game when it is in its final version)
bye :)