This black and white video from Indonesia documents the offensive against the Japanese in Indonesia during WWII. Flame thrower seems to have been a popular weapon, though a bit clumsy in my opinion. I would hate to be the operator of a flame thrower, as you end up having to carry this fuel filled canister on your back with questionable effectiveness compared to the same volume of shells.

To make matters worse, flame thrower is only effective as a weapon at close range. If you’re in an enemy territory and get spotted by someone who’s a tad further than the range of your torch, you’re a dead man. You can’t even run or hide with that thing on your back, leaving you completely defenceless against a person with a fire arm.

From source:

Death by flame thrower during Pacific War. The 1945 video shows the Australian 7th Division attacking the Japanese in Balikpapan, Borneo, Indonesia.