Your teacher probably likes them more because they are more varied in body tipes, all the robots were "fit" which... okay, makes sense for robots, Buuut... yeah. Here we go from anorexic to obese, from old to young.

It makes for a good contrast with the other group, since this shows variety, whereas machines are "made in a series" sooooo yeah. I get it.

But maybe point it out to your teacher that having two teams that use the same themes would be counterproductive.

And that since machines are built and artificial, making them have bodies that express "perfection" is part of why they are machines. They did not become so, they were designed so.

Yeah I also get why he likes them. I agree
I was kinda new in drawing sci-fi. I know I did what I could with those characters, now I know that I can do better. With these, I know I could do better then, but I was so tired already. So that's why I don't like them that much if that makes sence

¯\_(ツ)_/¯

makes perfect sense to me.

As a rule of thumb, to make "better" robots...

...think of how real robots look like

...and how machines work, and try and merge the two things.

Don't feel constrained to the fact that since it's a game...

...people would want to play a humanoid thing.

Or even if you do. Think that the humanoid could be a pilot. Maybe a tiny one.

Make robots quadruped, tanks with a torso, anything.

Don't confine yourself to just humanoids.

And even if you have... think of how you can play with shapes.

R2D2 is basically a trashcan and BB-8 is a ball.

Even if the assignment asked for humanoids.

You could have integrated those shapes into their designs to have more variety.

Think of the Portal multiplayer robots based on the Core and Turret designs.

Or think about stuff like mechwarriors.

Give robots 6 legs and a turret or something, like the tachikomas, now give them the ability to stand upright on 2 of those.

Basically... i get it... it's dreary, it saps you. Because it's a chore.

But, in a way... it also prepares you.

Because when you will be a professional you will have to do "chores".

On which will depend your ability to keep pushing forward.

And your personal income.

So good luck. And thanks for sharing.

Yes, I really need to push my imagination more, and be free with drawing those starting shapes. I went through one short cource this week, there was a little bit about that.
Thank you for comments and the encouragement! I really appreciate it.

Honestly, i appreciate you showing us your work, thanks.