I liked this a lot actually! It can get quite laggy closer to the end of the survival time, probably because there's so many. But, IMO that's not going to be that easy to "fix".
The way I see it, I'm a beginner in Godot for first time using it in this jam, and pretty much brand new to game dev altogether. I feel like even if Vampire Survivors came to my mind (which it didn't actually) I'd probably intentionally never go for cloning it for this time limited jam (much less, maybe even at all).
One, there's way too many enemies. Trying to make this not lag even a bit less than in just yours, even when there's already not nearly as many enemies as there are in that game (let alone super smooth), from what I found is not really a beginner-friendly topic area. at all - maybe not even an expert-friendly topic either!
Two, it's web, and I think web like you did is better for jams. But even the actual Vampire Survivors, if I understand correctly, is definitely not a web game. To make this work well and work well in web, means you probably have to do more super hard stuff than the actual Vampire Survivors release actually did themselves. It's hard enough to do this well on Desktop, from what I found, and for web it's probably even harder than that.
I'm surprised I'm seeing so many Vampire Survivor clones in this jam, wonder why last stand and Vampire Survivors came to so many different people at once and even appeals to them. If it even appealed to beginners, that makes it even more surprising. Ironically I feel that Vampire Survivors may be one of the hardest games to clone for experts, too, so that's.... very interesting to me. Also, even after cloning it, one may have to figure out - what makes yours stand out from Vampire Survivors - even after you cloned it? And that can be even more involved than cloning it in the first place!
By the way, cloning or attempting to clone Vampire Survivors tends to bias me against the submission believe it or not. That means I like the way you did yours, for some reason, and something you did sort of outweighed it. Otherwise I probably may have skipped, commenting, rating, or even playing it. Since I did yours, I probably just really liked the way you did your game.
So, good job making yours stand out!