Could you add an energy regeneration timer? I know that energy regeneration is slow and why it's slow, but I like knowing exactly when I'm going to get more.
I'd like to love this game, but the mission objectives to level up are just irritating, couldn't you have just made experience. At least that would feel more attainable.
Thanks for the feedback! We're re-working this system - the new one will have more "counter" type objective options like this, where you'll be able to earn a bit towards the next level each stage, OR complete the skill-based objectives to reach the next level.
I almost worry that something like this would anger even more people who think it's too slow :\