It’s an interesting idea and has potential. I like the different speed options. It’s great that you can build bots from different parts. Maybe having parts be of different sets, giving bonuses if you have a complete one, could be a fun addition. It would help give you an idea for what build to make.
When building the bots, it would be nice to see what part goes into what slot, even if it makes sense that the head is first and legs are last. Also, when you choose your loot after winning, it would be a good idea to add a way to see the parts you already have. When trying to find parts to build a new bot, I could and up with two heads and no items and/or no legs because I forgot I had a spare one.
Good submission!