Yeah. Benchmark game was always too opionated. It does not use JMH for JVM-based tests and the choise of problems gives a lot of advantage to lower-level languages like C. In this case the results a laughtable, because the performance of kotlin program should be exactly the same as for java program excluding some rare border cases with lambdas.
People probably will fix that in no time. But the project itself is not fair to JVM from the beginning.