My favorite shapes are definitely triangle and diamond, their special feels significant and add a nice twist to the gameplay. Hexa was my least favorite, because surviving was not really my issue. The stats from the upgrades in the lower right felt a little underwhelming, like I put all my points in damage and attack speed, but i need the same amount of shots to kill. Thats just a balancing issue though and I know thats hard to nail and takes a lot of time. I like the minimalistic aestetic and overall enjoyed the game pretty much. I'd say its a good base to build upon :)