Sorry for lack of detail and thank you for your response. It is a 2.5d platformer. The level has parts where I am using my normal character control fsms. But at certain points, he enters a tunnel where the player will be constantly sliding through it. The design is to have it play similar to Donkey Kong's mine cart levels.
I need to have the player always moving along the global x-axis in one direction, but I also need to have him be able to jump as well.
I have tried to use "add force" along the x but that didn't turn out too well. And I can not use "move towards" because then jumping and gravity will no longer be actually usable.
I hope this is clear enough.