I started working on a new bigger enemy type with destructible weak points but that did not go very well. Its bigger body revealed many problems with my character controller that had to be fixed. Even after all that, it just didn't feel fun to fight, so I put that work on hold to get something else done.

Here's one thing that worked much better: Stun modifier to projectile weapons. It is especially useful with those annoying fast-moving enemies:

Even though I stopped working on the new enemy type, I still like the idea and will likely continue to work on it later on. This is how it looked (ugly temporary model with glowing weak points):

Next up: Stun device that stuns enemies within certain range for a longer period of time. This should be fairly straightforward to do, now that all enemies have the stunned state mechanism implemented.