Drain

Welcome to an underground world you have just been dropped into that have been left in ruin. Platform your way through with your trusty battery backpack to make it out before this hostile world takes you whole! There are bystanders inhabiting this world, going on with their lives, maybe some of them will help you on your way!

The last sentence refers to a complex mechanic where every bystander can have different personality types ranging from outright hostile to helpful.
Every non-hostile bystander can give the player a measure of power as long as the player doesn't do any kind of action that will scare the given bystander (the player character is a strange creature in this world after all).

This project was created in a quick game-jam which had the theme "Drain". The theme was applied multiple ways: drain water, drain batteries and drain power. The jam ran for 2 weeks only. This jam ended with a resounding success.