I noticed that 38th place is bronze tier. For comparison In the first Halite 397th place was silver.
I can't remember the exact levels, but I think it was something like 1/4 were silver or better, 1/32 were gold or better, 1/128 were diamond? The tiers also seemed to update dynamically as more players joined. It's fun as you are getting started to see your bot move up in tier. The way it stands right now most people will never reach another tier.