I didn't understood all that well how to play. Are you supposed to jump into the falling things to cross?

Seems like a minimalistic Out Of This World/Another World, but even that game had some minimal hand-holding to make things clearer. 

I see a lot of potential with this game, but maybe it could be a bit better explained.

It feels like things are a little too random and hard to tell where the safe jumps are.  It might help to switch to a portrait view so the player could see more above and below them at the cost of seeing further ahead.

I like the idea. It was a bit unclear to me when the falling objects will stop, so that i can jump on them .

I like the idea, but its clear that its a prototype. For a prototype it's important to establish that your game is fun. For that, I'd like to see a bit wider where the possible jump locations are, because I'm sometimes waiting for too long until a suitable jump position appears. Sound, visuals and effects would polish this game.