You can use the options menu in the main menu, or use ALT+Enter.
Most of theses enemies weren't really designed with the lewdness in mind. It would be hard to make an animation that works. The closest to a common enemy that could be lewdable would be the cockhugger, but even then, that enemy (And its name) was basically a remnant of a very early prototype of the game that changed a lot since then. Common enemies are also, like the name implies, common. We don't want the player to be stopped at every corner with a lewd animation, or even clutter the screen with too many dazed enemies. Making the common enemies lewdable with the same system also means increasing their HP to be able to get dazed, meaning slower progression of the player overall. It would feel a bit like a slog.
It's all a lot of small details like that that we have to take into account ^^
I mean in all truth, the few i've come across and fought. Cockhugger self explanatory. can use for self pleasure or it can have its way with you, egg you and you die a few moments later.
The falling star (or whatever it was) can just land on head and done (blowjob). The bones that spew flames, well... coil you up constrict and bondage/burn idk.
There are options, but ultimately its up to you guys what you want to do with the game.. not us.
Clutterwise, you can always limit things on the screen. Metroid did it pretty well where enemies would only be so many on the floor or areas and not overwhelm the player. They did this with patrolling or jumping mechanics in different directions.
The floor crawlers would be spread out where theres enough but not all at once on screen (ultimately maybe 4). They had the big bugs that would jump around two go in one direction jumping same time or two in opposite directions.
There were also Spawner tubes that would spawn them at regular intervals and if they reached a point die out or disappear off screen to respawn.
there are many ways to work this around (and you are using unity engine if i recall) programming it with just an off the screen collision or "move to" can send the thing back to its position or just further off again.