Reminded me a lot of A Dark Room. You got a lot done in a short time, nice job. It's also great to see another mobile friendly game.
If you keep working on this here's my suggestions:
You need more explanations- I think ExpPts Collector unlocked the next level Haste but I'm still not sure? Cost so you know if you just need to wait longer, or you've maxed out. Item pickups like the pick axe should let the player know what it's for. I still have no idea what the difference between P and EP is, or even what they did for me.
Make it harder, I didn't even know there was a hearts/life system until the button came up.
Like vennnot said the castle loop needs more variation, not just layout but monsters too.
I think generally you need a bit more connection between the level up and castle loops, maybe a results page which could also add to the explanation.