i like it 5/5 and it should instead of making normal co-op next time maybe it should be online multiplayer and as pustulio said a graphics thing so u can lower graphics
i honestly think the badge should be easy because you can easily get to like 500-600 kill with half and with other weapons maybe 1000 kills but i didnt try after i got to 500 with each weapon which i still havent done with all weapons but its going on my favorites with a 5/5 ^_^
im not gonna say it as an easy game but it wasnt a hard game either but 5/5 for goood visual appeal and a game that give you something to actually think about