I thought of some of these actually, while others I most certainly won't add.
- When the mothership feature works well enough, I was thinking about adding enemy motherships which attack you. You as the player do... something, they warp into the orbit of your planet, you have to board them and it's basically a dungeon satellite, yes.
- Giant robots? Not sure, maybe. There are robot villagers at least. I was also thinking of floating robots which shoot lasers at you.
- So you mean, a planet which isn't even visible until you have a certain device? Not sure how possible that is... Might be too difficult
- I have a few ideas for mobs, I was thinking of cat people on Bastet, certain variants of the Ghast somewhere, or jackal-like humanoids with golden pseudo-egyptian attire which carry energy-shooting staves, at least
- "Strange Names"??
- What do you mean with "RPG adventures"? TwilightForest-like stuff most certainly won't be added, sorry
- Not sure about portals in space. Might be non-trivial to implement. Also, wouldn't "universe of the endermen" would basically be The End? I was thinking a variant of Endermen randomly boarding your ship while it's in transit using a warp drive, though.
- What kind of "Special Mobs"?
- Meh dungeons. I admit I don't fully "get" how GC's dungeon generation works. Maybe if I figure that out, I could do something. I added a pyramid with a few rooms and a boss/treasure room, though.
- I think I'll add jet fuel rockets, powered by jet fuel obviously, then ion drives, requiring power and Nitrogen or possibly Xenon, if I add it, and then the warp drive, which will consume only energy. Or maybe I'll just skip the rockets entirely. I'm somewhat concerned with adding too many different fuels, having different kinds of engines on your ship might make it too difficult to actually calculate fuel usage.