1. Not really; due to hardware limitations, Atari2600 sprites are always 8 pixels wide; ways to work around this limitations would be:
- Either position the two players side by side, to simulate a larger sprite;
- Or use NUSIZ0 and NUSIZ1 to stretch the sprite horizontally:
-- See: https://www.randomterrain.com/atari-2600-memories-batari-basic-commands.html#nus...
-- Unfortunately, VCS Game Maker does not support those variables, yet: https://github.com/haroldo-ok/vcs-game-maker/issues/47
2. You would need to program that; please see this discussion: https://forums.atariage.com/topic/213127-hm-how-to-do-a-simple-jump-command/