Nice foundation! Some notes:

- I think a thumbnail and some screenshots would really help draw more eyes to your game - they don't need to be anything fancy, but having things to look at is always nice to have.

- Marking the options button as not working or greying it out would have been nice.

- The basic idea here is cool, but some explanation on how to play would have been appreciated.

- The sprites are pretty cute! However, without a background, it's hard to make sense of where you're moving, where you're going, or even whether you're moving at all.

- I'm impressed with how you managed to make the gun track, but I'm not sure it opens up the most advanced gameplay - mouse controls could work better, or if you want to keep the lock-on, at least having the player fire manually instead of automatically would be nice.

- The lack of sounds or effects does hurt a lot, honestly - any sort of feedback for hitting the enemies would be nice, perhaps some damage numbers, a bit of knockback or screen shake, a sound effect, a particle effect, anything would go a long way.

- I also couldn't tell whether I was taking damage - I assume health hasn't been implemented yet, but some sort of a sound and/or particle effect would help a lot.

- You mention a tilemap, but I don't see anything here that requires a tilemap - is your game perhaps broken? All I'm seeing is a big gray background.

I assume this is VERY heavily work-in-progress, and I don't know where you want to go with the gameplay itself, but hopefully these can at least give you some ideas on where to take the game from here! Good work getting this far, I hope you keep developing this game and make it into something you can be proud of! (Or, if you did more and it just isn't showing up for me, so sorry about that!)