I beat the 33 enemies and no light bulb. Plus I can't interact with the King Bot anymore
Is it possible you didn't actually take out ALL 33 bots while still "alive"? (maybe you shot the last bad guy just as he shot you?) What happens to your character when it's killed while connected to The Brain is you reappear in front of him, disconnect the cable, return it to your inventory, and the Brain stays in that slurping coma you found him in. In which case you have to reconnect the cable and go back in to re-kill all 33 bots
When you take out all 33 bots WITHOUT running out of health points the Brain comes back to life, takes the cable from you, pats you on the back, and gives you the bulb you need.
If that's not your situation then you should re-download the game. (we've seen many cases of corrupted downloads)