Once you purchase the armor upgrades from the vendors the game becomes way too easy. I personally thought the end of the game would be the hardest (because of all the enemies) but I completely forgot that the Resistance gives you the extremely powerful Authority Pulse Cannon. Plus, ammunition is very plentiful throughout the last mission.
151/152 games completed (including DLC)
Completion percentage: 99.90%
Latest retail completion: Crysis
Latest arcade completion: Dust: An Elysian Tail