To make a river on the playing field in VBB?

[alfredtdk]

I'm using Pitfall 2 as an example, I want to use my character jumping from land to water, but with restrictions, I don't want him to reach the deepest level of the river or a pool, like Harry does in Pitfall 2.
In my knowledge as a beginner, I understand that I must create collisions in this aquatic environment so that the player does not reach depth and is just on the surface of the water, correct me if I'm wrong.
Another doubt I have, would a river or a lake inside a playing field be formed by a missile, sprite or ball?

[+atari2600land]

If you're using Batari Basic, you probably aren't going to get a very detailed river with waves and stuff. It'd need to be a straight line. You'd probably use the playfield blocks to make the river. You really don't need collisions unless there's something in the water for your guy to get.