This is a great example of taking a simple core concept and making an enjoyable challenge out of it. There's very much a constant mental analysis of finding safe places to stand. While it starts quite slow, the difficulty ramps up nicely to where I found myself making positional errors or being overzealous when attempting to collect coins: Risk vs Reward.
I would like to see some visual indication of when a coin is about to disappear, so the player can more easily make moment-to-moment judgments. There were times when I would decide to move for a coin only to have it vanish with very little feedback. Additionally, the prompts for what I'm about to buy might be better placed in a dedicated section of the screen that does not obstruct the view of the corner.
Overall, very fun and well put together!