Hello! It's great to hear from you! I'm really glad you liked my character. It took me quite a while to create the original design. I actually started by using the Sentry outline as a base and then heavily edited it until it became its own character.
My original idea was to make her a female dragon-like enemy that could swoop down from the ceiling. However, I felt that might overlap too much with the dragon from the previous game, so I decided to redesign her as a lizard instead. I also thought that fit better with the reptilian vore theme I've noticed throughout the series. if you put this character in the game plz put in her abilities it would be a hard enemy too as she does melee damage AND long range damage.
Since you asked, you have my full permission to use both the character and her abilities in the game. They're completely free to use, and I have no issues with you implementing them if you think they'd be a good fit.
As for the upgrade machine, I had an idea that might be fun. On the side of the existing upgrade machine, there could be a small compartment that the companion squeezes into, compressing itself until it fits inside. The machine would then rumble, shake, and make a few cracking noises before going quiet. A moment later, the slime would ooze back out onto the floor and gradually reform into whichever companion the player selected. I think it would be a fun little transformation animation while keeping the process simple and fitting the game's style.
as for the hostility between the aliens and the crew, i'd be better for the alien to be alone with the crew member before eating them its tactical knowledge and when eating them, the alien (after 2 seconds) fully digests the crew member after they struggle enough times. (you can choose the crew anyway but keep it so that the alien eats the sentry, dasher or scientist just a fact)
and also about how you said about the sandbox mode i kind of meant like a make-your-own-level type of mode where you get an empty platform, some tools to spawn in enemies and change their hostility and all stuff like that but i like your idea too.
oh and btw if you didn't like the armor on the original lizard, here is a different version without it
thanks for replying again see ya