The game graphic is classic, it's like old-school horror game (More interesting than realistic graphics) maybe keep it that way.
The longer you play the more you get bored because of the game being repetitive each rounds.
I do not know why some rounds there would be 5 robots spawned in.
It would be funny if you could fall INTO the lava and try to jump out.
Make the map more wider.
Expand the map so the players could run further into the map without having to easily get cornered by the robots.
Give wave break each round.
Character skins?
Overall this game was fun in the beginning and it just get bored overtime with the game being repetitive. I'll give it 8/10