Transformers: Decepticons is a video game made for the Nintendo DS by Vicarious Visions, and published by Activision on June 19, 2007, in North America, and July 20, that same year, in Europe, based on the first Transformers movie directed by Michael Bay, and uses multiple locations and items from the blockbuster Hollywood film.
Transformers: Decepticons is just one of the two versions of the game released for the DS, with the other focusing on the Autobots, their rivals, and has its story concentrate on an alternate narrative of the movie, which sees Decepticon missions take place in locations like Qatar or the Hoover Dam, with characters like Megatron, Starscream or Blackout being fully playable.
The current unlockables and hints apply only for the Decepticons version of Transformers for the DS, not for the Autobots one.
HINTS
Defeating Bumblebee
Follow him and shoot while doing so. When he stops, attack him while jumping When he takes off again, repeat the strategy.
Defeating Bumblebee and Barricade
In the level where you chase Bumblebee as Starscream, follow him until he transforms. To kill Bumblebee, jump around him in circles while shooting both guns (light and heavy). When he dies, Starscream will have the Alspark and Barricade will attack. There are two ways to kill him. The first is to move left and right while shooting your heavy weapon. When Barricade transforms, jump off the building and destroy trees. This will restore your health. Climb back up and repeat the process. The other way is to transform and fly back and forward while shooting.
Defeating Ratchet
Before you start the "Ratchet Retaliation" battle, make sure you are a helicopter. When you start, transform. Do not worry about the other Autobots; just fly back and forth attacking Ratchet. If you get low health, there is an area with tanks. Attack the tanks and most of the times they give you health.
Check out a trailer for both Transformers: Autobots and Decepticons below.