too many games!!! which are legit? (morte)

so ive gotten tons of games for my behold offa mortes list - amazing list, btw. anyways, ive also downloaded the zip files offa rapidshare or 4shared that are a bundle of games. in the bundles ill often find a game under the same name as from mortes site, but the size (kb) is different, sometimes by quite a lot. is there a difference in the games? obviously if there is none id rather download the smaller one, but what makes it smaller? lower resolution, limited gameplay, what?

i dont think that really makes a difference because in the bundle itll often have two games only itll say one of them is touchscreen but the filesize is still the same.