Transformers: Revenge of the Fallen

This (and it's Autobot equivalent) are probably the toughest Trophies in the game. In order to achieve a Platinum medal within a mission you need to complete it in the fastest possible time. I recommend using the transformer you are most comfortable with (I personally favoured Megatron) for the majority of missions and Sideways for the races (also the Deep 6 mission can only be completed using Starscream).

Concentrate on getting through the fixed objectives within each mission as quickly as possible, as in many cases the objectives are only progressed by defeated enemy waves this means defeating them quickly and efficiently. Once again headshots are your best friend as they also help to build your Overdrive meter quickly, generally you will only be able to use Overdrive once per mission so use it wisely. Also in some missions the last one or two enemies can run down the clock by taking their time to even reach you, where necessary learn where they're coming from and chase them down. In other missions enemies can be ignored so don't waste time doing anything that is unnecessary.

Collecting all of the Skill Shots will earn you an extra 50 seconds which is vital for some of the missions, learn their locations but more importantly learn to work their collection into the mission itself - if you spend 8 seconds hunting down a Skill Shot then you've only benefited by 2. A lot of time is also wasted whilst traveling as transformers move very slowly, therefore get into the habit of driving/flying as much as possible. Use Advance Jumps when climbing a building straight after driving and basically use every trick you can to shave a few seconds here and there.

Finally if you're sure you're not going to achieve the Platinum time in a mission then pause and restart rather than finishing and waiting for the mission to reload. If you get really stuck on a particular mission try this thread over at X360a which also contains a number of very helpful videos courtesy of Flik.