I've decided that this will be a NES styled platformer. I've chosen the NES resolution of 256x240, with 8x8 tiles, thats 32 across and 30 down. mainly though, the platforms are 16x16, or 4 tiles. I've changed the NES pallet to DawnBringer's 32 Col Palette V1.0 which has a slightly darker feel and fewer colours. I've also relaxed the number of colours the NES could handle per sprite. Other restrictions I try to adhere to.
I've drawn some key character sprites by hand in aseprite and right now, my main platformer mechanics are in there. good collisions and simple things like ladder climbing.
My gameplay will be quick levels that are timed. There is a little story to glue the game together, but mainly i'm going for the authentic feel of a NES game. Since I have an Apple and an Android developer thing, this game will actually come out on mobile when I'm done here, because... why not ;)
I'm putting this game together in YOYO games Game Maker Studio. It's nice and quick got this and suits the requirements.