Okay, so I tested this in English bc my German knowledge was definitely not enough for this TvT" I am usually not a fan of games with time limits - but this was surprisingly engaging, and I actually kept this on my phone to play whenever I have some free time~
Generally, I'm very fond of the concept - especially the campaign mode with the flower modifiers, it makes the game feel somewhat like a roguelike with randomized upgrades. By the way, the book is a great addition!! I loved unlocking all the various opponents and seeing which unique mechanics they had, and having all that in encyclopedia form certainly pleases my completionist brain.
The art and UI is also very thematically fitting - can't say the same for the audio unfortunately, since whenever I started a level the music would only play for a few seconds and then stop. I thought it'd loop, but it didn't. That didn't really detract from my enjoyment of the game, though!
The difficulty is a bit challenging, but not so much that it's impossible to beat - I guess you could make the beginner levels a bit easier, but that doesn't feel completely necessary to me. However, I agree with one of the previous comments: if it's currently not possible to change the way the combs are spawned, there should at the very least be a free reroll each fight, because a couple times I ended up with a board with literally zero vowels on it XD
Overall, great job on the game! I've had a lot of fun playing it and I'm really interested in seeing where it'll go in the future :>