Jurassic The Hunted

When you first pick up the grenades, immediately do a 180 and 3 dinos just jumped over the wall in the distance and they are coming across the field. Aim just above the middle one, throw and you will get all three of them. If for some reason you don't (grenades are very powerful in this game) there will be 3 more come over the wall in the exact same place.

If you do miss them all in this area there are plenty of opportunities to get this achievement during normal play in the game.

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Thank you and Good Luck!!

Easiest place to get this is the level "Vortex Zero":

At the very start you will come across three raptors eating a pachycephalosaurus this is literally at the start of the level. Do not fall down that cliff--its about 4-5 feet and you can't get back up...thing is the Deinonychus can't either. Get the raptors' attention and they will eventually charge towards you and group up for a grenade right in front of you below the ledge.

If you miffed it, just wait where you are and three more will eventually come for a second try (between 20 and 50 seconds maybe?).