Welcome to the forum!

First things first, the UI can be improved greatly, I know you tried your best and you are new in the industry, but you need to make it look better, at least the alignment of items being shown should be better.

I opened the Hi-Lo game, and the items are so large that you need to scroll up and down to see the whole screen, and even after scrolling up, the card doesn't appear complete from the top. You should make the size of each item small so that it fits in a single frame and there shouldn't be a scroll bar available on that screen.

I also have a question. Since you mentioned that the HI-LO game offers a 2:1 payout ratio and if one bets with 500 Sats, they get 1000 Sats for a win. Does that mean your HI-LO game has no house edge? Does that apply to real money as well or it's just for the demo mode and it will be changed when you launch the full version?

Edit: I have noticed one more thing in the HI-LO game. A popup notification tells you how much you have won when you win a bet, but there is no popup when you lose. Why is that? There should be a popup for the lost bets as well and it should show the amount lost, or at least show that the bet has been lost.