March of Swirling Mist Processes Wrong
This card doesn't function correctly on iOS and probably other platforms. In normal play, when you cast the card, you enter the value for X. Then it normally askes you how many blue cards you want to use to reduce casting cost. If you use zero, you are used to just clicking this for"Submit 0". Then you select X number of creatures, then also click the Submit button. If you have picked no creatures yet, it says "Submit Zero". Then the spell casts.
However, if you have no blue cards in you hand, the game skips the initial "Submit 0" for reduced casting cost, and goes straight to the "Submit 0" for targets. But you are used to clicking twice, so you instinctively click past what you think is the first "Submit 0" and it casts the spell with no targets.
It shouldn't ask you for two inputs normally, but only one input when you have no blue cards. It leads to constant inadvertent mistakes!
To make matters worse, if you cast the spell with ZERO tagets because you made that mistake, the game should ask you "Are you sure? But it doesn't, it just casts for zero targets, and it usually costs you the game.
Please fix it so casting for this card is consistent, and that it at least prompts with "Are you sure?" if you select to cast the spell, then choose zero targets.