Easy peasy lemon squeezy :v
Sadly you couldn't add more, but I really liked the difficult curve and how you presented it. The first level you start with the bar full, so you have plenty of time to think, understand and act. On the second starts low, so you have to recharge. On the third, when you want to teach about staying in the light, the torch extinguish almost instantily. Really well done, congrats!
If you eventually try to make it bigger, what I suggest is restart in the same level instead of going back to the first after each death.