Our games are pretty similar, except yours is a survivor-like and mine is just a general top down shooter. I don't really have any criticism to give, to be honest I liked everything. This isn't a criticism or anything like that, but I think it would be cool if you were on the beach and had to defend the shores from enemies that came out of the ocean, that way your arena would be more interesting and you could possibly treat it like a tower defense game as well.