Excellent suggestions, thank you!
>add a line in the “more info” tab about the meaning of ↓ and ↑
Will do.
>use ⌊…⌋ and ⌈…⌉ instead.
I actually wanted to do this at first, but I am afraid these symbols may confuse less mathematically-inclined players. At least arrows have some vague intuitive meaning to everybody. I am unsure of this.
>an option to disable/delay tooltips
This option exists, Settings -> Hint delay. Set it to 5s and just press Ctrl whenever you want to see tooltip.
I am sorry for inconvenience -- do you have any ideas on how to make it more discoverable?
I also agree that current default is very annoying but I am afraid new players will be unable to discover tooltips at all if I increase it. I am still struggling to find optimal solution.
>an option to play a card with one click, without selecting it first
I will consider it. Don't you think it will cause too many accidental misclicks? On the other hand, is will not hurt to add an option.
Meanwhile, maybe you will like to play with keyboard? Press space to play selected card. Full keybindings are documented on 'More info' text tab.
>maybe at all try to avoid tedious optimal play
This requires deep discussion. In short, game has many 'grind to win' options, which is half-intentional.
While adding counter to items is indeed on my todo list (not just for this reason, simply to open more design space), fixing just those two cases is completely insufficient. For example, you can just as tediously gain infinite life by playing Weightlifting with Echo/Miracle/Swindle, or just Stop on Precipice.
One idea is to add some global 'turn limit' mechanics to prevent this together with various soft-locks. I vaguely considered ideas similar to 'sandstorm' form Bazaar, but so far has not come with good enough plan.