Iron Grip: Warlord (PC) (2008)

20120912:
Today I played a single-player level and from I can recall (as of 20150213), the game was difficult, but unique.

The difficulty, however, must have stemmed from the fact that I was terrible at first-person shooters (I'm still pretty bad at them, but there's been a marked improvement).

In any case, what makes Iron Grip: Warlord unique is its blend of first-person shooter and real-time strategy gameplay (tower defense). After setting defenses and making repairs in RTS mode, switch over to first-person shooter mode and take down a soldier or two with your own bare weapons.

While Iron Grip: Warlord was probably unique in 2008, various tower defense games have since been released which blend a second, action-oriented genre. These games include Sanctum (2011) (+first-person shooter), Orcs Must Die! (2011) (+third-person action), and Dungeon Defenders (2011) (+third-person action RPG). Furthermore, these three particular games have spawned sequels: Sanctum 2 (2013), Orcs Must Die! 2 (2012), and Dungeon Defenders 2 (2014, Early Access).**

Personally I enjoy Orcs Must Die! and Dungeon Defenders more than Iron Grip: Warlord. Not only do they have better visuals, but the gameplay is also more fluid.

Steam Achievements:
10:18am Can't Keep a Good Stronghold Down
10:33am Power from the People
10:41am Decimation