Really cool idea.
The first bit was very confusing though, I was expecting a combination rather than to have to hold it for several seconds.
The rhythm was pretty hard, I blew myself up.
Ah, don't worry about making short games, I wouldn't expect more than a few seconds of gameplay from a 3h jam game.
I think part of the problem of the first part is that the sounds are rather unpleasant.
If the rhythm game had progression, maybe two shorter sequences beforehand, then it would be a bit better I think, because that would allow you to get familiar with the sounds before you need to remember a long sequence.