Really cool concept of a tower defense game. Definitely would love to see a more polished development of this. A rotating hex grid TD game is definitely something I would like to see get a bigger release.
Things I wish were different. Audio, even if it was free royalty free music and sound fx generated in something like BFXR or Chiptone (both free online), should be in the game. It feels really odd to sit and play a game you are focusing on with zero auditory feedback.
I also wish you had a bit more impact on deciding where towers would spawn and what you would get next, even if it made the game harder in other ways.
Another thing I noticed, more importantly was the towers have zero aim leading, they fire at where the enemy "was" rather than will be. This means that the towers can hardly hit enemies at range, other than the dual shot one, and some enemies like the really fast one (because of this it should have way less health) are almost impossible to defeat, because they are pretty much too fast to be hit aside from the limited time they are in point blank range.
Alternatively to adding this, you could go the route of letting the player spawn tanky minions on a lane, more like kingdom rush, that would stop up enemies for a bit and let the towers hit them. Or another idea would be making the projectiles "semi-homing". Honestly though, all in all, I think the towers definitely need to be more accurate.
Aside from this, encountered one bug, where a tower would spawn inside another ("locked?") tower, and it would jam up the cell, eventually you could get it to unlock, but it would get stuck for awhile spinning backwards and forwards like a physics glitch in a game. I think this ended up leaving me with invisible towers that stopped me from rotating certain cells properly and made the game way harder than it was already.
Please don't take the negatives as thinking I really dislike the game. I was looking forward to playing it, and I would be interested to see if you take the concept of something like this further.