I'm making a minigame within the project I'm working on in RMXP. The player rides down a river and has to avoid hitting the obstacles. I've run into a problem, and I was wondering if anyone could help me out.

I want the screen to autoscroll down, and for the player to move with it. I figured out how to do this, running the event as a parallel process. Because there is already downward motion, I want to disable the 'up' and 'down' inputs from the keyboard for this minigame only. In other words, the player can only self-determine left and right motion. How can I temporarily change the allowable player inputs? I tried making the river tiles only passable left and right, but this makes it so the player won't move with the screen scroll because the tiles are no longer passable in a downward direction.

Thank you for your assistance.

Maybe you should move everything else besides the camera and make the obsticles and such move as a parallel process. You could lock the camera and have the area beyond it lined with collision events while the obsitcles move in from off-screen with a scrolling paralax of the river (with collision events at the edges, of course). That way, you can move the guy anywhere on the screen in the river and teleport the obsticles back to the top of the screen so that you don't need that many events.
There's probably some other ways of doing it and I'm not even sure if it will work due to running out of my XP free trial but it should give you some good ideas.

That's a really good idea. I had finally ended up setting each tile as a single-move scrolling action upon player contact, but the game's a bit laggy for my liking, with all the events. I think I'll give your system a try. Thanks for the help.