I also had a bunch of browser prompts pop up at the start, but simply hitting "cancel" on all of them let me play without (as far as I could tell) any technical problems.
A little bit of instruction in the comments would have been very useful: having the light "off" to begin with left me completely lost as to what was going on (and the character seemed to simply float around randomly and reset occasionally until I first turned on the light: I'm not sure if that was because hitting the button did something to initialise/reset the game or I simply couldn't see what was going on, but it made for a very confusing start).
Greater care with the graphics might also have helped communicate what was going on. I don't mean making them "better" in a more general sense - which is probably not the most effective use of time in a jam - but thinking about what you want each sprite to communicate to the player. The platforms seem to be photos rather than a representation of something I'd expect to be able to stand on, for example. And the hammers seem to fly directly towards the player, so why not make them some object that would ordinarily be expected to do that - maybe arrows or cannonballs? (I also noticed that you can keep playing the game even after a game over - not exactly a serious oversight but something that could potentially be addressed if you wanted to refine this later.)
Theme-wise this seems a great match for the jam, by the way. I feel like a lot of people went with lights for the on/off element but this makes it nice and central to the gameplay.