Transformers Decepticons is a third-person, free-roaming adventure game in which you play a completely new robot in disguise on Earth. Your new robot comes in the classic bad guy colours of black and silver. Because you're a brand new robot, you have the choice of what you want to transform into. All you have to do is scan a vehicle and you can transform into it, and the vehicles range from pickup trucks to fighter jets. Your main aim in the game is to destroy the Autobots and the humans they're defending. There are also side missions to complete, such as destroying as many buildings as possible in a certain time limit (appropriate, considering you're an evil robot.) The Decepticon Version of the game has unique dessert levels unlike the Autobots version.
The touchscreen serves as a map, showing where your enemies are, your missions and your current target. It also shows your experience level and how far to go until your next level. The main use of the touchscreen is the transformation button which instantly morphs you into the last thing you scanned.
Online you can get into deathmatches, play Allsparks Soccer and get into an Allsparks War.
In the Allsparks War you have to join a faction and download a daily mission. The better you do on the mission, the more points you earn for your faction and the more unlockables you receive. The different factions scores can are compared on the game's website.
Protect Or Destroy The Earth with Nintendo's Wi-Fi - Nintendo Wi-Fi Connection enables players to engage in the "AllSpark Wars" where they must help their side win the global conflict between AUTOBOTS and DECEPTICONS via daily challenge missions and global player stats comparisons.
Battle Again and Again Alone or With Friends - Each Nintendo DS game features 20 unique story missions plus more than 20 challenge missions as well as local wireless multiplayer modes (up to four players) such as Team Death Match and AllSpark Sports.
More Than Meets the Eye - In addition to playing as some of the most well-known TRANSFORMERS robots, fans are able to scan over 30 unique vehicles and customize their paint schemes. Gamers can instantly morph from a larger-than-life robot to a high-powered vehicle, such as a sports car, fighter jet or helicopter, as quick conversions leave enemies in the dust and enhance player's combat strategy.
The World Is Your Playground - Players take on enemy AUTOBOTS or DECEPTICONS to build up their custom TRANSFORMERS stats and abilities. Both games feature huge open environment city levels which include Casino Town and Hoover Dam while Antarctic levels are exclusive to the TRANSFORMERS: AUTOBOTS game and desert levels are featured in the TRANSFORMERS: DECEPTICONS game.