Yoo, I used to make games in LibGDX! Cool to see people still use it!
The game was pretty fun to play. It's very difficult to have to select a card effect on yourself, which actually makes the game more fun, since you have to evaluate if you have enough time to use a card or if you should focus on attacking.
The difficulty was also very good, and I managed to get reasonably far without the game feeling to easy or hard.
One small issue is that the music doesn't start until you die once, so the first playthrough is silent.
Also, most people like me don't like reading too much text, so you should try to make the tutorial screen a bit less dense. The game is pretty simple to figure out even without it!
Overall, very nice game!