The main reason of the long time is my lack of free time. The development was frozen about 9 months last year due to personal issues. Most of the first months I spent on the project I had to redo most of it, since I changed the way to do things as I was learning how to code properly.
I ripped the sprites and tiles myself. I later discovered sites like the sprite repository, and the spriter?s resource, but I already ripped everything I needed. Then I re-ripped some of Samus? animations, just to have them properly aligned (that?s why she runs so naturally, compared to other fangames). And ripping tiles is time consuming too, but after a few tilesets I discovered VBA?s debug tools, that saved a lot of time.
And there are things you haven?t seen yet. Making the SR388 levels took about half a year, most of the first temple rooms were revised or redone. Making each room requires object placement, doors scripting, camera scripting (just the big ones), and hidden area scripting (some places). Making the demo you played took about a month, most of the time was spent on level design and testing.
Among other things are a couple of enemies more and the stacked beam system, it works but it still needs some tweaking and balancing.
By now I showed you the basics of a Metroid engine, what I considered is polished enough to be shown. And even then a couple of bugs were discovered and reported. (thanks Mason, I?ll look into those)
I posted about the development time in the project?s blog, feel free to take a look.
I could have shown you the engine a year ago, and it might be as cool as it is now. I showed it now because, right now, I know the game can be finished.