Interesting concept, trying to defend the body from viruses - with a flamethrower no less! It felt like there was so much world and content to explore in this game, and it's always good to have more game. Using a flamethrower as a weapon was a great idea too, and it was fun to just burn things around you, even if there were no enemies. The game did feel a bit slow at points, though, so faster movement and smaller levels could've added a good bit more action to the game - and more opportunities to use your weapon!
The art was brilliant, and the backgrounds all looked perfect as the internals of a body, so great job on them! The enemies looked positively terrifying as well, and the lighting effects of the flames helped make the game look just that bit nicer. The use of darkness and a flashlight helped fit the horror theme of the game as well, as did the background noises. The heartbeat especially added to the ambience of it all.
This was a nice, spooky entry to the jam, and I found it a lot of fun - nice work!