Just finished playing through the game. Here are my thoughts, some sugestions and some ideas.
Overall, I enjoyed playing it. I actualy finished it and that says something, since I turn most indev games off if they don't entertain me in some way from the start. Inventory works well, the game has actual pathfinding for main character (which is something even big games don't necesarily have) and I didn't have a single crash or any serious bug.
Here are some things that could be improved:
Doors. One enemy stood in the same spot door were and I just kept opening and closing the door instead of attacking him. Best solution would be to give the player the ability to only open them. Not close them.
Small hitboxes on some enemies. The temptress is a good example. You have to click on the model perfectly to actualy start atacking and that model is pretty thin, making me just walk when I click and the enemy plays an animation. Model moves, I click the empty space, which made me miss sometimes. Solution would be to make the hitbox bigger, or making it a bubble.
Character slowing down while moving through doorways in a specific way, or past enemies. Not a huge problem, but still noticeable and slightly anoying.
Dropping items is iffy. Right clicking item in the inventory drops it, but draging it outside and clicking drops it and then character walks to the spot the mouse clicked. Personaly, I would prefer if you could drop items only by draging them outside without your character moving. Right click could be used for equiping / using items and droping them quickly could be done with shift+click.
No enemy health indicator. Adding a healthbar for the currently targeted enemy at the bottom of the screen, or just changing color of their name depending on their health would be better than not having it imho. I would also like to see some graphical effects for hitting / getting hit by an enemy. Blood splashes, bones flying,... Things like that.
Repetetive sounds. As far as I could tell, most activities have a single sound option. Attacking, enemies dying, enemies getting hit, footsteps etc. This could obviously be solved by adding more sounds, but making every soundeffect play with different pitch level every time it is played would improve this too.
Too many potions. By the time I finished the game, my inventory was completely full with potions. Obvious solution would be to spawn less, but that could be hell to balance in later stages. Other option would be to let potions spawn only if the player has less than let's say ten of them. Next option would be to make them stackable by five or ten.
Range of spiters seems too long. Personaly, I would change their attack to be like a mortar. Firing a projectile in an arc that explodes in a small radius in the place you stood while it was fired. This would diferentiate them from the skeleton archer a bit more.
It would be nice if the golden goblin had actual UI that opened together with your inventory when you click it, showing three slots for the items. It took a few moments to figure out how he worked.
These are the things that came in mind. Ofcourse, there are more but these are very obviously in the works and not implemented yet since the game is still in development.
Here are some "wild" ideas. Some things I thought might be neat. They might be good additions, but they might just sound good writen and be terrible while actualy finished.
I liked the simple lighting and I wouldn't mind if the game was darker. Light could probably serve as a new resource. Having multiple sources of light, like strong but quick burning torches or weaker, but longer lasting lanterns could make things more interesting. Strong light could make enemies weaker or reveal secrets stashes. Weak light could make enemies stronger, but will make them less aggressive, so it would be easier to pick them off one by one.
A simple arena mode independent from the main campaign could add some replayability. You start the arena mode, select a dificulty and be spawned into a large room with some enemies and a boss. Kill them, get some loot and xp and be teleported back. Sell your items, buy new ones and be teleported into new room with new enemies. This could go on forever. Upon death, highest room reached will be saved in a high score board.
It would be nice to incorporate past characters into new runs. Adding a strong zombie carrying one item from your past character or just making your previous character who won a boss you have to fight. Something like that.
Anyway, that is all I can think of now. Wish you good luck and hope you enjoy developing your game.