EngagingEngagment

"All characters in Vampire Survivors

Vampire Crawlers contains 22 characters. There are two steps to obtaining new characters: First, you must discover them, and then you can recruit them at the Inn in the Village. Recruiting new characters requires a certain amount of coins. You only need to purchase a character once; whenever you're back at the Inn (after a dungeon crawl), you can swap between your unlocked characters at no additional cost."

Which game are we talking about again?

Can't speak for how the Anime is going to turn out. Can only speak to what I've seen so far from the Manga:

No filler.

Everything is in service to pushing the story along.

Author appears to have a clear idea of the story they want to tell and an endpoint in sight. This doesn't seem like it's going to be something that gets milked for all it's worth and keeps going well after it should have ended.

World has some interesting ideas it is playing with.

There are definitely some standard tropes. The older cool "mentor", the villain that is a sort of frenemy that helps the MC get stronger through competition etc. It's still definitely a shonen battle manga. Everyone's got their own taste, it might not be to your liking.

For myself this is up there with Full Metal Alchemist as far as story, character development and action. I hope the anime stays true to the manga and doesn't end up full of extra stuff.

Agreed, I have no idea where this author's definition of TTK came from. For the entirety of time I've been familiar with the term it has to do with how fast an opponent dies after you start attacking them.