In the current version of the game, when I click on a card that I can't currently play nothing happens whatsoever. I think I should get some kind of explanation for why I can't play the card. For example if I can't play Vicious Thrust because I'm affected by Spore Cloud, if I click the card the game should remind me that my character is halted and thus unable to play the (step/move) card. Currently I feel like I have to click a few more times to see if it's lag or misclick or some other problem, and then I have to search the map for some game mechanics that might prevent me from playing the card. I think it would be much nicer if the game just told me explicitly, perhaps with some mouse-over text or something like that. Otherwise it sometimes isn't obvious why clicking the card doesn't work. (eg. Vicious Thrust prevented by Spore Cloud, or other actions prevented by stun cards, etc.)
Or have the preventing card pop up when you click. Because of my computer and net connection, I sometimes do have to wait several seconds for the game to respond to my clicks. And sometimes nothing happens until I change focus to another tab or program (a net problem I've had for years, though it had mostly gone away until I started playing CH).
Would be good in most cases - but remember that some cards can't be played for their own reasons (e.g. Violent Overswing if it's the last card in hand)
