It may be because of your keyboard; a lot of them can't detect a high number of key presses at once. If you have another keyboard you could try it, but I'm sorry, I should have thought of that when designing the game; my bad :(
well it's the keyboard built into my notebook, so I cant exactly exchange it :-(
I meant plugging in an external one, but if you can't, don't worry (it isn't my best game, either way...) °^°
