Since this is taking inspiration from Packedrat I have a few ideas based on what I think worked well for it that could also work here. Of course I have no idea where you intend on going with the story so many of these might not fit but here they are anyway.
- Being able to bait certain enemies into each other causing them to grapple and use each other like you could with the kobolds in Packedrat.
- Wide variety of enemy types, not just bipedal. I see you've already got a flower type thing which is a nice start. Some ideas for other enemy types could be Insects, Ghosts, Plants, Dragons, Corrupt Machines, living latex (Changed comes to mind) etc,
- Themed zones to house different enemy types. Cursed forest, Slime cave, Abandoned Factory, etc.