/vr/ - Retro Games

Ok please - how do these games fucking work? Are the dynamics actually deterministic of the inputs or not? I am trying to play Sonic 1 I can't get any feel for what the mechanics are so I'm trying to break it down into little tiny cause and effect tests.

So at the bottom of this S I want to go back in so I jump into the little quarterpipe thing, trying to land near the lip and press down to be a ball. This usually (!) makes me get speed that shoots me most of the way back up in the S. But inside the S without even pressing anything I can hear sonic go PSJJ PSJJ at random(?)(!) intervals. So I come out with a chance of having enough speed to launch from the quarter pipe, and a chance of not. I can see the S has some kind of pusher inside but it's just random?
That's one obvious source of randomness but also when rolling on the flat coming out of the S (again pressing nothing) sometimes sonic kind of jostles on the ground and gets a bit of air before the quarterpipe which kills the transition to it and you get no air.

So is it random or there's a timing aspect that you can get a feel for, or what?