As someone who has played with developing Atari home-brews and was once a big Odyssey 2 fan (I still have it and over 30 games including the muti-cart) I have to say I want to do a O2 port but the odyssey 2 natively supports many more sprites. A new 2600 kernel would need to be written but the sprite flicker may be too high a price. I am playing with the batari multi sprite kernel and have created a simple tung-in-cheek Odyssey 2 game which I'll post soon. Me and my Atari 2600 and 800 owning friends back in the 80's were hooked on UFO, Pick Ax Pete and KC Munchkin. I do think that Attack of the Timelord or Freedom Fighters would be the easiest of the more popular games. Oh yes I also fell in love with Killer Bees later that decade.