The game was fun to play. Lacked a few more traps, and perhaps different kinds of goblins, like hob-goblins and the likes. Also, as stated in a previous comment, hotkeys for placing would be nice. Also for when wanting to place multiples, it'd be nice to not have to go into the shop each time. Also, rather than a shop, I wonder if it'd be more immersive if there were simply buttons at the bottom of the screen rather than having to open up a dialog.
The characters bobbing around was kinda hilarious. The game was however a wee. bit too dark (referring to the lighting here). Also I'm not sure if the goblins cowering in the corner until they get killed/ escaping the dungeon are a part of the game or a bug. However if it's part of the game, perhaps some speech-bubble of the goblin saying "screw this, I'm out" or similar to show that it's intended would make more sense to the player.
Also, music and some faint growls as well as just some sound effect for battles would add more immersion I think. And showing health-bars for goblins, damage indicators during battle and timers for the spike-traps I believe would also make it feel a bit less random.