For a game in some of its earliest stages it is already quite fun, obviously there's a lot of room for improvement which will come with time, development and growing the amount of resources you can use. With some better art, a more fleshed out story, larger cast of characters, etc. It would definitely scream a good indie game to play especially since it seems the only IAPs are going to be DLC set aside from the main story,
Personally, I believe the very first zone needs to be expanded as it is quite a small zone considering the maximum level for xp percentage growth is 10k it would make sense for the final boss to be slightly below or slightly above 10k, slightly above sounds better as it would force the player to be smarter with their stat assignments
Second thing is that progression feels too easy but also too hard in the sense that after roughly 3 runs all equipment slots with the first character are unlocked and probably 5-6 runs with the second character. The second character took around 10-15 runs before all bosses were beaten considering the attack + Crit + Initial Combo melting the health on any enemies. I believe I beat both final bosses with a final health of 1500 and defence of 7800. The first character in contrast feels a lot weaker obviously more targetted towards health which is quite useless given the enemies gain a dmg multiplier after 11 turns with each turn afterwards increasing their multiplier by x2 theron. Ideally it would be better if they gained damage reduction for say 10% with a 10% increase for 5 turns followed by a dmg increase of x2 or 10% for another 5 turns allowing the player a bit more leeway. I have yet to beat the main story with character one, I have had upwards of 50k health on top of 100k damage a 50% crit chance and 4.4x crit rate and didn't stand a chance against the final bosses. It's for this reason that I think enemies need that slight little rework
The equipment also needs a bit of refining. For the 2nd character there is a weapon you can get after your last encounter with the blue haired girl that is weaker in every way in comparison to the weapon prior while being more expensive and ultimately useless outside of the 0.2% increase in xp rate. In general though equipment mainly feels quite useless, I like the idea of buying equipment but having more lootable equipment would be nice along with having some kind of weapon refinement/upgrading but also possibly a con for the weapons if they are "OP" or a pro if they are "weak". Say for example you have an axe that gives you 7500 atk plus 20% damage increase, it could have the con of reducing your agility and defence giving you a minus to your stats or you might have a flimsy sword that deals 500 atk but gives a permanent crit rate increase of 2x so if you had 3.5x it would then be 5.5x when equipped
Having a way to speed up combat and also flee from combat would also be nice mainly just for the whole speedrun aspect for those skillpoints, maybe attach that stuff to something like a relic system where relics are found upon monumental achievements like beating a zone within a time limit, losing a certain amount of fights, win a certain amount of fights with low health, etc. Things that take skill and dedication and reward the player with silly or serious artifacts that could benefit them or make their gameplay that bit more difficult. Again as an example, speeding up combat could be linked to the speed you beat a zone, faster you beat the zone faster you can speed combat up or fleeing from combat being a cowards way out from losing too many fair fights e.g fights which your current level could normally handle and also requiring all stat points to be used to avoid people just going to a level 100 zone as a level 1 to easily obtain the relic.
The art was another thing, that just comes down to having one solid art style, that will come when there is a budget that can be put into the development process of the game and a reliable artist to do that sort of work.
Again considering its in its earliest state its a game that had me hooked for a couple hours and once in its finished state I think I'd gladly purchase the game, don't undervalue it, once it starts to look good and play good there's nothing wrong with charging people to play it, a game can be made for fun and still help put funds towards either a sequel, expansion or personal life expenses and if the game is addictive enough with a thrilling gameplay loop, worthwhile story and sense of accomplishment people will definitely buy it.
Overall I'd give this game a solid 7/10 considering it being an alpha release. 1 point off because nothing is perfect another off for the art and the last point off for the progression regarding character 1 good job making the foundations of a worthwhile game!