Truthful in its nature of strategy and action, R63 is quite undeniably the last true tactical game to have come in the series.
Pitting you in a what-would-be a spec op's worst nightmare scenarios too crazy for real-life, you're given simple objectives that usually encompasses rescuing hostages, preventing certain destruction, and all the while killing everyone else in sight (enemies do rarely surrender though). The levels are great and complex, but some may prove to be too much of a challenge, with some of the most unforgivingly tough gun combat you'll face. As hard as it can get, this instead left me craving for more for some reason.
Enjoyment is however, marred by a few technicalities to the likes of the occasional dumb but crazy aimbotting enemy AI and slightly underwhelming gunplay. What's more annoying is the incompetency of your own teammates, who may fare well in the easier levels but get completely obliterated in certain, more assault-oriented levels. Ultimately it doesn't matter how much strategic map planning comes into play, it all boils down to the player's own level of FPS skills for the best success, which puts into question the real importance of the tactical aspect.

Regardless, this game goes far behind SWAT 4 as one of the best tactical shooter I've ever played. And given the state of the Tactical Shooter genre that has since died off in gaming trend, this position will always remain as such, sadly.