the names of the snakes were pretty funny and the game's concept is tried and true
different graphics for the different snakes would have provided more interesting variety
i also think the snakes are in general a little too expensive and get too expensive. maybe their cost should be added by a growing/constant amount instead of just doubling with each purchase, or give the later snakes a greater amount of coins per second or less of a delay
a more interesting addition would have been if you put more visuals or changed visuals overtime or something (a lot of games in this genre usually display little sprites of the stuff you bought in a space somewhere)
all in all, it's pretty good, but it could use some more polishing