The anti-g goes with them. They're not really dead since there are only 7 aliens in all, which may just be different colors. The real menaces are the alien animals. The transition from alien to human or vice versa would be an expensive process. Hence, use a cutscene.
All profs have the same body, either male body or female body.
The distinguishable feature will be the face textured from a picture. Cutscene beginning of crash, train falling, ruble blocks other door, title sequence. Levels need whacked lighting colors and maybe strange props. Items to be acquired will spin in place to make them obvious Look above or in the story page for more ideas.