I loved the visuals and the use of audio, They’re great! It got me a while to guess that you just need to survive the attacks to win the fight (I’m still not there yet), but after noticing the background and the change in music, the smile it put on my face is a great indicator of a job well done (imho). Definitely gonna try it again later.
As someone else already commented, the story connection between pantheons is a bit weak and the introductory part is a bit too long, but neverthless very interesting! Maybe you can make the font a little smaller and make less cards, but I’m not sure it’ll help in making the player feel the introduction is shorter.