Basically two simple things
1. Every user get randomly scrambled coordinates for every run
2. When you eat - you get only a part of prey mass, the rest is distributed as feed. When teamers recombine the mass with friends them mostly lose from this more, than win from prey. When single player eats, he get less than mass of prey , but it's always positive income.
+ a couple of things are locking minions and feeder bots. Boter account can be locked forever. Skills based game always is victim of bots.
Ok, I get the Logic. And it is quite impressive. Yes, unfortunately, am far from Netherlands right now so I guess it will be very difficult for me to play.
I would suggest putting some stats like the total number of users playing right now and total amount cashed out with the leaderboard. That will make users more aware and try more in the game.