These games always stress me out! I enjoyed this one more than most though, you managed to make the vibe much less pressured and I appreciate that.
My immediate thought for feedback is that a bit more background would be nice - a sense of there being a wider restaurant setting, some kind of character response if you do a good, bad or middling job of preparing a burger. I did notice, however, that you only had about six hours to work in, and you've done a phenomenal job in that time! I'm approaching the suggestion as an 'if you took it further' type thing.
You've put together a complete gameplay loop that with a couple of practice goes makes sense with two buttons. I enjoyed the squeaking sound from the sauce bottles very much. It sounds like a little thing but actually I think it speaks to the level of polish you've achieved in so little time. Well done!