Simple Answer. Game is too difficult, terrible level design, progression is exceptionally slow, downtime in action is too long for an RPG.
Might seem like ranting.
People don’t like negative consequences like dying that much. I only killed 3 peasants then dying after that. Waiting to regenerate health kills the action, players would have to wait 100 seconds to fully heal and get back in the action, d’ya know how boring that is? After dying three times, I tried to look for an alternative option; explore. Thinking I would see some secrets of some sort. I met with this innocent looking guy and I thought he was an NPC, so I went closer and started chasing me. I tried to survive by hiding in the castle, thinking the knights would save me. Yet they killed me. That frustrated me.
Game Progression is slow, killing a peasant only earns you a meager amount of coins, remember for a fact that I have to wait 100 seconds to regenerate to full health and get back to action, I forgot how much the next weapon cost, but I knew it wasn’t realistic to achieve in the next 10 minutes. To aim for the perfect completion time, set an intended goal. This set time will be when the game ends. Ask for game testers with ranging skill levels and time them, you can try to recreate skill levels yourself too.
Game Replayability and Retention isn’t a factor on how long the game is. It is how interesting the game is, how much replayable mechanics are introduced, and how challenging it is, etc.
You failed significantly on level design, the aspect of observation. When players are given a task, they observe, strategize, then execute. When I was playing, I wasn’t quite sure who the enemies are, so when I strategize and taking actions on my plans, THEN seeing them fail is enough to frustrate me, and argueably, all players. You need to communicate your level design well(quest design is a part of level design). Use Visual Language to communicate this well, there are alternatives, but this technique relies of less handholding and leaving the player to their instincts. Adding a simple backstory to the first NPC encounter like: “We need to kill the King and his subjects” would be enough to tell the player that everyone in the environment is an enemy. Never let players to assume things for themselves, with exceptions of course. Things need to be straight forward to resolve that problem with the confusion and remove some of the frustrations resulting from that.
You might consider adding telemetry and data collection, see where players leave, how far they progressed, and if they play again. You might set these in zones so that they give you a narrative or a hint where it might be too difficult and frustrating. Try to limit the downtimes in action, don’t bore the players by waiting, if you do want to keep some of the downtime, try to push the player into exploring. Don’t let them be bored, but there are times where downtime is used as an effect.
I don’t like to nitpick on individual things like GUI, UX, and usability, in my opinion they aren’t that helpful. Prolly not a biased statement since I am a UX designer too. Man, I like writing walls of text. I am too passionate for game design.