Bad gameplay design. Actions are slightly delayed or attacks last longer than their animation. Moving forward is as everyone else had said just plain annoying, as is the limited coin collection. Not moving forward as much/at all and a larger coin magnet as well as tighter controls would improve this immensely.
@Zachaius, in hard mode you only get double jump when you have the "D" special unlocked. Re-activating (I assume you mean clicking inside the game window after clicking outside of it) is completely normal for any game/program.
The closest thing the game has to a friend system at the moment is the Lock option. When you're playing in the vicinity of someone else they appear in the bottom right box, clicking on their name gives you options like teleport, trade, and Lock. When they are locked as long as you are on the same map (In the same server and not in separate dungeons) They will always be in that box. You can teleport to them etc easy now. This saves through death, if they change their name, and if you leave and come back.
SPOILER ALERT! http://www.pirongames.com/blog/2009/06/orbital-decay-story-transcript/ So all the enemies were humans raised and commanded by you from the past. You get to the past by destroying the you from the you from the past that have a JumpGate onboard. so it explodes and makes a vortex that sucks you in, taking you back 15000 years, with no humans to control you. So instead you raise the humans to the evil ARU you fight. Then the Future you comes and you want to have a Godly showdown, and you die, making a wormhole to send them back and become evil again..repeat repeat repeat
Once you get bankers guild there's no deposit fee :) It's a need when hitting bosses that are going to kill you 10 times. You can also store your items like demon ring so you can use them later and they don't take up space. And +10% is sweet too.