I think it's a cool idea, but I also think you should slow down with the story. It seems like you covered a lot of ground in one short piece. Add some meat to your new series.
Something like this...
Ep. 1 - Describe the facility that Radio is in and his impression of it all.
Ep. 2 - First introduction to the Drakos character. Maybe a conversation between him and Radio in which Drakos explains why Radio is there, what he plans on doing with him, and what purpose the tournament serves. Radio's refusal to participate results in him being roughed up by security or something, have him locked away.
Ep. 3 - Have Radio talk about his time locked up. Maybe he meets some of the other fighters in the tournament. You could probably stretch this over 2 or 3 episodes actually. You have endless possibilities with space prison!
Ep. 6 - Radio is finally ready to kick some alien ass after being put away like a caged animal for days.
Those would be just the first 6 episodes and I haven't even gotten to the actual tournament yet. It's not just about stretching the story out either, it's also about giving us a better idea of the type of world Radio is trapped in.
Ep. 7 - Maybe you go into detail about some of the other fighters. Nothing big, maybe a brief dialogue or a one paragraph background on each demon/alien. You mentioned Street Fighter in the RP and I was thinking you should try something similar to what that game does with its characters. Instead of 16 random, crazy ass aliens, create a group of 8 and give each of them a picture and a brief description/background. It doesn't have to be in great length, just something like
Jeth
This asshole is from the Phoenix galaxy and likes to sink his dagger-like claws into his victims. The claws are about one meter each and could split a human being in half like a log. To make matters worse, this monster stands well over the seven foot mark. I should also mention that he fights naked. I would probably fight naked too if I had skin made of armor.
Yeah, it's not that great, but I'm just going off the short description you gave in your RP. You could add a few other details about him.
I could keep going, but I don't know if you'll even like this advice so I'll stop now.
Hopefully this helps, let me know if you need clarification on something.