I feel like this could have used a better on-boarding experience. Once I got the hang of it, it feels like a much more put together idea, but the game seems to be "check folder, see if it's one that matters, if not back out immediately without consequences, then move into a new folder and repeat" which is a very simple loop.
My suggestions:
1. Have risk/reward tradeoff for folders clearly established. Yes, you have the heart pickups in some folders, but the heart pickups are never worth fighting an enemy for.
2. Really, the minesweeper play is the interesting part of the game. Having a more "territory" based gameplay (as you have with the locked files/folders) as part of the core and just refining around that "find the mine, destroy the trojan" gameplay would make things a lot smoother.
3. Enforce commitment. This is something that falls more in that classic roguelike vein, but the "leave without consequence" function is something that makes browsing folders more of a casual experiment than a real challenge.
I think the core's really good, there's just some extra distraction around it and once you clear away that distractions there would be a lot of space to work with a more conceptually centered foundation.