Haha well it is very nice art, so it does stand out when so many games have generic looking stuff. If it was me (and again, maybe everyone else loves this style of game - and also, I'm just a player and not a game designer) - I'd definitely lean more into the theme and unique abilities even if the hover-attack thing remains. I really liked the idea of "The knights are coming!" at the demo end. Personally, I'd ditch the "Your timer ran out!" model for ending rounds and actually make some villagers/knights/other enemies come and attack so the vamp has to go hide. That would open the door to new defensive type upgrades - your minions can fight to protect you, but maybe also some entirely new defense ones, etc. Maybe even add a new scene - the interior of the vamp's crypt, with some slow-running time-based currency with a second upgrade system to unlock features, strengthen existing features, something like that.
I'd probably buy it on Steam either way, but I'd pay more if it was like that :D