I'm open to making alternate grab animations based on health, it's mostly just a matter of putting work into animations. Extra animations means more work time and higher risk of burnout, with most of the enemies here already having close to 100 frames in total. Making finisher animations longer is definitely immediately doable though, and a rework is planned for the finisher script to allow them be be a lot more varied, and have individual stages. Being able to manually accelerate them is something that I'm looking at, I just need to make sure that it doesn't outright replace the respawn button (I don't want people to have to button mash if they just want to go back to the save point).
I just mentioned this while replying to another post, but the gallery is going to be unlocked through discovery, with an option in settings to unlock everything if you just want to use the gallery without playing through the main game. This is mostly to incentivize exploration and prevent any spoilers that descriptions might give away (which are currently being treated as teasers for future areas lol). I'm probably going to have a thing that shows the number of enemies discovered vs the full count, so there's still going to be a good idea of how much there is.