Every time you use your Car/Jet mode's superior speed to get close to a Mook, shift forms and immediately launch a melee attack without stopping.
Pulling off a successful ram in heavily armored Truck mode.
Using your tank mode's turning ability to outmaneuver a car or truck and finish them off while they try to figure out what you just did.
When Megatron is being chased by Omega Supreme, he is very reluctant to run away from the special super-robot trying to kill him (and who could kill him with a single direct hit), actually daring him several times to come and get him.
Two words: Atmospheric freefalling. To further elaborate, after you force Trypticon back into his natural state, he begins freefalling down to Cybertron from space and you keep shooting him as he does so! The best part of it all? It's entirely playable.
The first time you play the Autobot campaign and you hear Optimus Prime say "Transform and Roll Out!" No matter who you play as, you'll be pumped to pressed the button to transform.