I think the game is great and fun, however, I feel that the graphics could be better (pixel-art, maybe?) and the UI (especially the bit where it tells you the controls) could help and make it look more appealing to attract more players. Hope you take this constructively and consider my points, Jamie.

I like the idea but the graphics need a big overhaul. Overall fun though!

The art style is great, and the level design. The controls need work as I feel cramped to have to press O to shoot and L to interact. Maybe try mouse buttons? See if that's better. What's also annoying is the physics. Whenever I let go of the space bar, I fall back to the ground extremely quickly after jumping. Decrease the falling speed or whatever you use to make the player object fall? Try that. Thanks for the game :) From Jamie.

Thanks for the advice! I thought the sound was a bit loud too, so I'll see about turning that down. I will definitely add more ways to get ammo and more enemies into the game because that would be great. :) Thanks for the advice, Jamie.

Also, if you're interested, I just uploaded a new build which features a new enemy and particle effects. Thanks!

Thank you very much! This is my first published mobile game so I am extremely grateful for any feedback. Did you play it when there was a levelling system? This update released around the time of you posting this, so I am unsure as to what version you played. I would greatly appreciate any feedback on the newest version if you feel like giving it a go!
About your suggestions, I completely agree. What power ups do you feel are most necessary after playing the game? Changing the backgrounds is a great idea I can work on also.

Many thanks,
JamzDev