I tried out the game and the first impression was very good! The farthest I reached was stage 6 so far.
First of all I like the many different card types you implemented! They are creative and it's very fun to try out different combinations.
At first I misunderstood, that some cards do work relative to their previous and next slot. But that actually makes the system even more interesting!
Furthermore do I like the effects. They pep up the visuals a lot. It definitely feels rewarding to watch the many many glowing projectiles on the screen after trying out a new set of cards.
However, in my opinion the player projectiles are too intrusive. They do look nice, but they also mix up with the enemy projectiles a lot, which makes it very difficult to dodge them at some points.
I also want to say, that I really liked the music! The track didn't especially fit the gloomy color palette of the game in my opinion, but it did still sound very good and contributed to the overall game experience.
Compared to the ingame sound, it was a little silent though. Not sure if there was an option to adjust the mixing. If I missed it, I'm sorry.
I'll definitely give the game a few more tries!