Everyone should get this game, it's ridiculously fun for $10. Basically... the gameplay is as follows:
Each level has 5-6 lanes - straight line paths from the right of your screen (where the zombies come in from) to the left (where your house is... and as a result... YOUR BRAINS).
During the round, zombies spawn and walk straight down their lane, chomping whatever's in their way (there is 1 plant you can construct that pushes them into an adjacent lane, but that's unlocked quite a bit into the game).
You construct plants to combat the zombies. Plants generally fall into 4 catagories...
- Resource producing
- Direct damage (straight-line projectiles, usually)
- Protection (tough plants that don't attack but have tons of hit points)
- Utility
You get so much playtime for you money it's quite hilarious, and the tongue-in-cheek humour in the game is a nice little addition. Dancing zombie is awesome, yes?
Anyway, yes, buy it.