During the last couple of weeks I was able to observe a couple of playtesters going through the current version of area 4. Luckily, this time the area miniboss isn't as unbalanced as Arachnus and Torizo were in their earlier versions.
In fact, quite the oposite happened with the overall battle difficulty with normal enemies. Samus has access to Plasma Beam and the Screw Attack in this area, like in the original. After getting these Samus is pretty much invincible, and enemies need to be very tricky or have annoying traits to pose at least some challenge.
I even added a new, original enemy. But I can't seem to find a middle ground between it being cheap and just being a moving target.
So, there's the posibility of moving one of those major items to be found on area 5. This might require the redesign of some rooms, and more testing.
By this time, in the original game, once you cleared the tower and chose your beam, you went directly to the Omega nest. It made sense to be fully prepared by that time.
Now, this is where I need to depart the most from the original level design, specifically with item placement.
In the meantime, Area 5 was redesigned from the ground up. It will have some unique events, like all the other areas do. The layout is on paper right now, and it will need to house the item moved from Area 4 too. But I was able to give the existing rooms a new location and functionality, so production of this area won't take that much, level design wise.
Things are going a bit slow, but any progress is good.