First off, I thought the game was genuinely well made, but there are some things that I would like to bring up, especially since you're aiming for a commercial release:
1) The gameplay itself feels a little repetitive, and honestly kind of pointless. I get that it's an endless game, and you're supposed to keep trying, but for me, I didn't think the gameplay was fun enough to make me want to play again without some sort of incentive. If you want to keep the gameplay loop exactly the same, something as simple as an upgrade shop that you can visit after making a burger would make me want to keep playing a lot more.
2) In my opinion, the use of the theme is kind of redundant. The way I see it, the button having two states doesn't really count if they're used more like a trigger rather than a toggle. You press the button once, and then it's replaced. I'm sure you probably expected this criticism, but I didn't see it anywhere else so I thought I'd throw it out there.
3) I wish there were sound effects. Having satisfying sound effect could've also made the gameplay more fun, just by adding a little bit of player feedback. In my experience, it only takes like 30 minutes max to find sound effects on freesound or opengameart and then implement them.
Now that being said, I really don't want this feedback to come off too harsh because honestly, there's a lot that this game has going for it. First off, the amount of features this game had was honestly impressive. Although it seems very simple, things like the leaderboard, the music selector, and the background selector really do enhance the playing experience (maybe this is where shops could've been implemented, like you had to buy different music/backgrounds?). Also, even though you did use other assets, the game's art and music really did mesh well and create a good atmosphere. I hope you improve the game in the future, especially regarding my first and third points, and good luck!