Glad you're enjoying it! I put some thought into making an interesting risk/reward healing system, but from seeing people's gameplay, it does seem a bit complex for what should be a simple action, as many people don't end up using it much. I do like the tradeoff of being able to hold on to the charge to get a damage boost though.
There's not really a progress indicator, but to give a general outline of the scope, after getting to the central hub zone, there's 2 areas you can do in any order (the forest with the Scavenger King and the electric area), after that you'll have to do a little bit of backtracking/exploring, and then you can open a short final area + final boss. Depending on if you already did the electric area you may be pretty close to the end.