I´m starting to populate Area 5 with enemies, Metroids, and some surprises. Underwater Metroid fights are quite challenging, but not unfair. Luckily, you won´t have to fight too many Metroids before you find the Gravity suit.
Some of the room layouts had to be changed a lot. By the time you get the Power Bombs, the enemies aren´t much of a challenge. So I had to rely a little more on environmental hazards (well, spikes) to keep things interesting.
There are some scripted events left to do, a miniboss, and some tile and background work to finish Area 5. After that, it´s just the Omegas Nest and the Queen´s Lair left to make. Compared to the rest of the areas, those two are very simple, level layout wise.
Like always, comments and forum discussion is welcome.