The beat engine seems to have some issue with playing more than 1 sample which has the same timing. E.g. if you set up the hi-hat and snare to both play on beats 1, 5, 9 ,13 then the hi-hat and snare samples are not played simultaneously. It seems like the snare sample is not played until the hi-hat sample has finished playing. Is there some issue with playing two or more samples simultaneously in your implementation? Or am I the only one having this issue?