I had an issue when keeping movement keys pressed, the game would pause while it finished playing sound effects. So, I had to slowly take one turn at a time.
I liked the hand drawn art, it really stands out. The enemies looked especially good. Lighting was nice and moody. The colour scheme was great. Again, made it look very unique and the HUD was clear and stood out well. Aesthetics were the highlight of your game.
The character UI goes off screen (I played it in fullscreen mode). I did like how you laid out all of the commands on screen, so I didn't need to confer with your game notes during play.
The voiced sound effects were a cool touch. Though the above mentioned issue did detract a little from them. Music would definitely have been a good addition. Even some ambient sounds.
I couldn't find any health, armour, or weapons pick ups. Even shooting a wall seems to cause injury (?), which is particularly unfair due to no health boosts or armour. After death, you could respawn in the ship with progress intact, but with enemies respawned, instead of the game restarting from scratch.
A mini map or even a compass would have been very handy as some of these caves get quite expansive.
With a few touches, this game could be really good.