It wasn't immediately obvious that playing meant moving pieces anywhere on the board but I figured it out quickly!
The pieces having different movement and attack patterns was a good mechanic but it wasn't always easy to determine which were which, or when attack tiles were fading in which piece was responsible. Even on easy mode the attack cycle happened just slightly too fast to account for but it didn't always feel unfair, just difficult.
The circular piece was a godsend because it was so aesthetically different from every other piece I could instantly recognise it and what it did - for most other pieces, not so much. Maybe their design could have used some color to differentiate them better, or a more referential style to help with learning to recognise them and their attack/movement patterns - it looks like the designs might be based on chess pieces but they're a bit too far from what is recogniseable to be... well, recogniseable in the game.
Seeing something that is obviously based on a Queen would easily read as something that attacks a wide range but even since the atttack/move patterns of pieces aren't the same as they are in chess (i believe?) it's another layer of learning. This isn't necessarily a bad thing but I didn't expect to be doing that much brain work to figure out how to play longer than ten seconds.
Maybe introducing a smaller variety of pieces early on to get the player familiar with their patterns before introducing more could help with this? And more visually distinct choices like the perfect sphere, I can't overstate how useful it was as a player to be able to identify a piece so easily due to its different to the others.
I'm sure playing a lot would familiarize you with the piece design so you would be able to think quicker but a lot of my play time was spent waiting for red/blue squares to appear so I could react to them, rather than strategically moving pieces.
This does seem like an "easy to learn, hard to master" game with a solid gameplay base. Some polish elements like animations, move/attack effects, and a more readable attack trajectory (like the moving pieces easily identified by the arrow pointing from them) would go a long way in improving the player feedback experience but the bare 'rules' of the game are good for a hectic burst.
Those menus are hideous tho lmao