A big qualm I have is how I have to press each character cards to reveal at the beginning. Would prefer having a settings mode to auto reveal all or a quick flip all button. After spamming games my desire to keep playing shortens drastically by the manual process of clicking each character. Overall fun, but fix this for sure.
It matters which cards you flip, and in what order. Some characters affect face-down character cards, some restrict what you can flip, and you also score more points the fewer cards you flip. Flipping all of them at once gives you a big disadvantage.
A hidden shortcut (holding shift while clicking, perhaps) would be a good idea for earlier levels, when it isn't as important.