I tried this mod and it was really fun! I love his Jet-pack Glide Ability and his emote. Tho I see that this causes some errors. And i see that this could get some improvements.
Soo as for the graphics, they look kinda small tbh, maybe putting then a little bigger would work. Here's an comparison (You don't need to change it if you want, it still looks good)
As for his height, it looks like he could get through there with no problems, but as this gif shows, the hitbox looks taller, i suggest maybe put the hitbox smaller too or make the sprites a little bigger. Maybe changing highresscale in the S_SKIN could work.
As i loaded my character skin, i noticed that it gave an error about play_rafxtra being already defined even through i didn't load it before Crewmate.
Now to dive in the mod's content, i also want to suggest some things.
These here don't need to be here in order to make the mod work, either way you can still have those if you plan to do something that contains graphics in it.
These also aren't needed, the MUSICDEF file was just a test i made to see if it corrected the lump of the secret music file i have in my mod and forgot to remove it. The midi is also just a Deltarune midi track from my mod, i'm not bothered by it but it kinda doesn't make sense being there since the mp3 and the midi aren't the same melody but you can still have that if you want to. I also suggest that you change the name to something like "O__CREW" instead because it replaces the music of my mod.
Here i can say that you probably just copy and pasted and didn't mind to change some things. To start "play_rafxtra" could be changed to something else like for example "play_amongemote" the same applies to "S_PLAY_RAFXTRA" and "MT_RAFXTRA" as the RAFXTRB is only used for my character's second emote. (So delete everything that contains RAFXTRB in it because it's not needed :v) In case something happens with the script, you can always call me for help by sending me a private message.
And also you forgot to credit me, as this also isn't needed, i would still like to be credited...
And at last, these sfx sounds here in the skin directory but this isn't important at all. If you want to keep things organized you could make a directory specifically for those sounds or move them to Crewmate's Music folder. (You can also convert the Graphics into Doom Graphics since the PNG Graphics tend to take more time to load iirc)
Oh and also you don't really need to say that's the final update lol
Besides these, the mod is really fun, you did a great job at your first mod and i hope you can improve like the others in this community. Congrats! :D