One big question that I ask way more then I'm willing to admit, will this game have a save feature? You were talking about porting it to other platforms so you are obviously skilled in the engine, making this more of a possibility.
I hadn't really considered it much before, but that does seem like a pretty good idea. The more experienced beta testers can get through the game in like 1.5 hours, but first-timers take a lot longer. I did my first full play-through a couple months ago and took almost five hours, and we've added a new stage and boss since then. It shouldn't be that hard to add, it would only take about 14 bytes or so to return you to a similar state at the start of your current level.
Edit: Just added SRAM saving. Nothing fancy, but you can resume your last game by pressing select at the title screen instead of start.