levi lost its rockets, which is why it isn't in use anymore (for rushing anyways). I think weasel is ok right now, the cyclone could use a slightly longer delay or more nrg consumption, but other than that it's fine.
I don't think that's possible with Continuum. There's a energy depletion green and a full charge green... there's no half-energy green. The only way would be to reduce your max energy... or have something shoot at you until you reach half energy.