Hey there MysteriousDeveloper, thank you for the subscribe on YouTube.
You might not know this, but I can not actually playtest on browser. I checked your other games and found Fun 1 interesting enough to make a small video about it.
I would recommend finding away to increase the ammo or upgrade to new weapons. It is extremely hard after few levels as you are going to be without ammo. The texture of the floor and walls made me dizzy after a while, that is why I could not go further.
However, I made a good video about Fun 1. Hope this helps xD