This is a really fun game! It kind of reminds me of Fantina's gym in Pokemon DPPT where all of the gym trainers have a flashlight that give off a triangle shaped range of light. If you get caught in this range, they battle you similar to how you get caught in this game.
For question one, you could possibly expand the range in which the enemies move. They follow a very predictable path so far so it's easy to strategize a simple route. Is it at all possible to randomize their movement or create 2 unique cycles of movement that gets tossed up every so often?
For question two, I personally love games like this so to me it's not frustrating but when I got caught my character completely disappeared off of the screen and I couldn't do anything until I refreshed the page entirely.