Is this a decent gaming PC?

This is a custom built gaming PC running Windows 7 Home Premium. It has an XFX Radeon HD 7850 video card, Gigabyte GA-G33M-S2L motherboard, Intel Q8200 quad core CPU, 4GB of Kingston RAM, 250GB Western Digital hard drive, and 550 watt power supply.

With that knowledge, could this PC run semi-newer games (around 2012)? Even if the graphics have to be bare minimum for the game, is it decent? It's only $250, which is fairly cheap and I'm getting it as a present to someone who plays a game with extremely low specs to begin with. (Conquer Online if you want to look it up)

However, I would like for him to be able to play games such as Minecraft, Black Ops, Dungeon Defenders, etc etc.

I'm not sure about the rig but you will want a much bigger hard drive and maybe even a solid state disk SSD