So I grew up with both Touhou and RotMG, so naturally I hopped right into this game on Windows, then Arch Linux. I haven't found much difference so far.
The controls feel like Rotmg for the most part. I changed the focus button right click for focus the since it hurt to move focused for extended periods using the default controls.
Difficulty is on par with a Touhou 2nd boss on normal. With the simple patterns, tiny hit box, and generous spacing, I was able to clear it with no damage and mostly minimal movement. Was a little disappointed at the difficulty, but considering it's in alpha stage I'll give it a pass for now. Consider patterns that brings you closer to the boss or at least can't be cheesed by sitting in the corner a la pre-vital-combat RotMG.
The aesthetics (you're working on these rn, right?) are OK if you turn off the FX. The filters make everything fuzzy on 1280x960 and 1400x1050, both windowed and fullscreen. The individual bullets are nice and bright against the dark background. Unfortunately the patterns were nothing of note. Again, alpha stuff. The rune affects while focused and the energy spheres were a decent visual touch while not being too distracting.
I turned off the music after the first few runs. It got old fast.
Overall it's a decent prototype. Good luck on finishing it.