Is there some sort of cheat you guys use to build these insane parasites or? I'm super bad rn and I kinda wanna see what the game has to offer but that's hard to do when you suck. Thanks!

No cheats, just farming at the Free Roam stage.

Here's a tip on how to rip through the stages:

Use the species that starts with the "Claw" zooid, and make a wall of claws. Charge at your enemies, attack with the Claws and watch as everything just dies. The "Jet" movement zooid of that species really helps with maneuverability as well.

I call this build: The Wall of Death.

Here's an example of what you should aim for.