To improve
First off a lot of collision issues. I should be able to walk left or right alongside walls. I shouldn't be able to hit goblins with my back.
The day and night thing is a nifty feature, but the way it was implemented make it more of a un-fun nuisance then something enjoyable.
Getting healing items was very infrequent and with enemies respawning every time you enter a room this became quite a pain especially since you return all the way back to home instead of the front of the dungeon like in Zelda.
There were some other bugs and lameness, but I can't remember due to being distracted by TV in the middle of writing this.