Week 2

Changelog (Week 1 -> Week 2)

Updated the way drag force (gravity_x) is calculated to make water currents work.
Added countermasures to prevent slide to transform over slidrill due to high speeds.
Drag force correctly applies when entering and leaving the drag force area.
Work on new backgrounds has begun.
Couldn't fix a logic bomb related to drag force; added a countermeasure. A bug becomes a feature as a result. First time for me.