Thanks for playing it! As for the export it's just the bog standard Project->Export->Web preset to an index.html. You'll be prompted to download the export templates but if in doubt just download everything.
As for getting it done in 2 days with difficulty is the answer. Second day was mostly brutally cutting everything to meet deadline, the shop is just a grid container with buttons and callbacks that I threw together in the last hour and if was going to take too much time the alternate plan was just give the player 2 of each die and call it a day. It's why I had exactly 3 tutorial levels teach, without them I don't think I would've submitted. I'm not super fast at doing jams, I've failed to submit in the 2 day Juniper jam earlier this month, so I'm not really the best person to ask on this. But it was just start on each problem I knew I needed to solve, pieces need to be able to be clicked on, they need to snap to a grid. So the mouse handling was one of the first things I did and the sprites I used were 64x64 so my grid size was a bit bigger than that. Just picking the smallest bits of work that need to get done and get done early because everything else kind of depends on those things getting done.