Really nice game! Your theme interpretation is super creative, instead of counting down time, count down possible paths to boss, and i like that it adds some strategic thinking to gameplay, you need to choose path wisely, some times opening room just to secure them for future (path to shop for example).
Only one major issue for me - standing combat, I think it would be better, and more paced if you add ability to shoot while you moving.
But overall great game well done!