1 - Carrot
2 - Turnip
3 - Mushroom
4 & 5 - Cucumber
6 & 7 - Eggplant
8 & 9 - Pepper
10 & 11 - Tomato
12 & 13 - Onion
14 & 15 - Watermelon
16 & 17 - Some kind of symbol that looks like a Galaxian ship (no achi for this drop)
Level 18+ - Pineapple

Since you can begin a new game by selecting any level you have already completed it is not hard to reach level 18, but it may be hard to do it in one run.

You must pick up the drop in order to pop the achievement, and the only thing this requires is dropping two boulders - it does not matter if they connect with anything, and you can die between boulders and still spawn the food.

I've played up to level 32 and not found any additional fruit, but I'm not sure if the pineapple is the actual last drop or if there is a mystery further on.

1.) Rambler - Dig 1000 spaces in 1 game. The achi does not specify this, but it is so. Each space is ~the size of Digger, and will require a practical minimum of 6 boards fully dug out to pop the achi. If you're wise with your tunneling you can pop it without too much trouble somewhere on board 7 or 8.

2.) Crush 4 with boulders - Make a long vertical tunnel and lure them to you, waiting until they are close enough to be unable to escape.

3.) Centurion - Kill 100 Fygar & Pooka in one game. Play to kill and not to get points and this is easy.

Use the customization and give yourself the maximum lives and lowest points for earning new lives and all of this should come with about 90 minutes of play time. Everything else is quite self explanatory.

Now you know how to party like it's 1999 :D