I had a quick go of your game so only a short review.
The font size is way too small. This is fairly critical and something you should consider addressing sooner rather than later.
It was actually unplayable for me, I couldn't read the text without bringing my face much closer to the screen, even then it was a struggle.
So I tried clicking all the buttons to see if I could figure out how to play. I clicked everything I could see and nothing seemed to happen that I could make sense of, it looked like I was buying things and I had to open a store in order to continue. With the amount of information on screen and the tiny tiny font size, I really struggled to figure out what I was doing.
I typically avoid reading a description before I play because I believe things should be intuitive and self teaching. I went back and read the description. It seemed to communicate what I had observed in game, that is I had bought some things and needed to open my store. No guide on how to open a store though.
I tried playing again, clicking all the buttons to attempt to open a store. I could see a disabled "open store first" button, but no actual button to open my store.
To answer your question: The first 5 minutes of this game was confusing. I had no idea what I was doing and felt like I was unable to actually 'play' the game.
"Unplayable" is the right word and I am glad you used it rather than softening it. The product names on the shelves were rendering at 6px. Not small, unreadable.
That is fixed and live now: product names 9px, department signs 10px, the stat captions and the instruction line raised too. On the first screen the share of text below 9px went from 48 percent to 20 percent. I picked 9px by measuring the longest product name against the tile width rather than guessing, so nothing truncates that did not truncate before.
The rest of what you describe is the real problem underneath, and I am not going to pretend the font fix solves it. You clicked everything, saw money moving, worked out you had to open a store, and still could not tell what you were doing. Four people have now said a version of that. The screen asks you to understand it before it lets you act, which is exactly backwards for something people reach by clicking a link.
Worth a second look now if you have the patience, but the honest position is that I have fixed the thing that made it physically unreadable, and the thing that made it confusing is still in progress.