Success rate measures the amount of code submissions that played the game/environment without failing (compilation, breaking game rules, violating sandbox, etc.), so it makes sense Python would do better there.
Percentile compares only the submissions that didn't hard-fail. So they are a bit different, and we incorporate them both into the combined score.
Comparing rust to javascript, the gscore is rather similar in distribution, while python falls off. I don't see why python should be so much worse?
This was an unexpected result, and it held up under large sample sizes.
Also somehow the 2 language comparison graphs (avg percentile and success rate) rank Python in dramatically different positions, with Python outranking Rust and Java in the success rate. What does the avg percentile mean in this context?