No worries! - Yep, I completed it second time around! - charming game, and very clever use of physics / ropes!
I'm not great on ideas, but I'm guessing even with this theme, and a less 'relaxed' take on the game's levels, you can have hazards like water, cutting hazards, etc, that you have to avoid, maybe items that need more than one power source (ie. like battery powered, where you need to add more units to power something up).
The game also actually reminded me a little like a top-down 'World of Goo', in the way that power supplies connect up - so possibly, you could start some levels with tangled ones / lines / items, and to reach a point to connect something, you'd have to untangle or even (gasp!) CUT some lines out, maybe not power related, I'm not sure - maybe even 'pushing it' (ie. dangerous!) type bonuses for maxing out a whole chain of 'em... :) ...just throwing random stuff in there... :)
...but yeah, I'm guessing you've a lot of ideas yourself!