Hello guys !
For that cheevo you must finish the game in Adventure mode in co-op (local only).It's pretty fun and easier with 2 players than the solo.But if like me you have nobody to play with you,you can beat it alone with 2 controllers.
Few tips for co-op solo:
- Start a Playthrough on Easy (seems logic ^^)
- Move one T-Rex at a time
- Don't play levels with zero sure spots (to let the 2nd player safe during you move the 1st player and vice-versa) or levels with timer
- You only have to get 2/3 of the stars to unlock the final boss,so you'll need to get most of the "No death" stars.Don't worry,if you have 1 player alive at the end of the level it's good.To cancel the star it requires that both players are dead in the same time so it's not so hard to get this star.
- Forget the "Speedrun" stars it's nearly impossible,except the bosses,to get them in solo.
Or you can try this trick: (thanks to FinalKaos to find this !)
I just replayed the last mission in co-op mode from my single player file and the achievement popped, might be worth other people giving that a go. I had started a second playthrough in co-op but only did the 1st level, so not sure if that made any difference.
Tell me if it works perfectly and i will change my solution definitely ^^
Good luck guys and don't hesitate to ask me your questions to make my guide better