Thanks for your suggestion. We can only change the vocabulary coverage for the next version of the course, and even there, "netopýr" would have to offer significant advantages to earn its inclusion because it is not covered in CEFR levels A1/A2.
It might also interest you that in Czech one is more likely to be as blind as a mole (krtek) or even a cartridge (patrona) than a bat. The cartridge thing comes from "slepá patrona" (blank cartridge).
In your translation, replace "jestli" with "že".