I like that you have a split second to react, it really makes it scary.
I tried a few times but couldn't beat it.
I'm amazed you got it working a a ROM and on the phone. I would love to know what you are using.
I used GB Studio. You can make some basic top-down games with it. It's pretty nice, but it has it's limitations. Due to some of these limitations, I wasn't able to get the enemies to disappear right away when you use the flares, which was a disappointing bug that I couldn't hammer out in time. If you use the flares in the same room as an enemy, the enemy "dies" but the sprite remains on screen until you walk over a tile or two. I'm sure there is a fix for it, but in all honesty, I got started on the project later than I had planned due to starting my new job and wasn't able to work that out in time for the deadline.