Here is the full list of all 15 Tembo the Badass Elephant achievements.
You defeated the PHANTOM Commander and thwarted the PHANTOM invasion!
You obliterated the third PHANTOM Dome.
You demolished the second PHANTOM Dome.
You rescued all the civilians in a zone.
You destroyed the first PHANTOM Dome.
You smashed the PHANTOM Lock.
You rescued all the civilians in a stage.
You destroyed all the PHANTOM enemies in a stage.
You obtained 10 Peanut Butter Jars.
Your training is complete.
You obtained 99 Peanut Butter Jars. I mean, that's a lot of Peanut Butter.
You destroyed all the PHANTOM enemies in a zone.
You rescued all the civilians in or around this island.
You obliterated every last PHANTOM enemy in or around this fair island!
You accomplished all of your Missions. You did it all. You are a supreme soldier. WE SALUTE YOU!