With free-to-play games in particular, it's critical for players to be kept happy. Developers do this with varying degrees of success. One that has done a very good job, at least thus far, is Hi-Rez Studios, the developer of Tribes: Ascend. The game's latest free update, Accelerate, delivers more than just new content; Hi-Rez is also answering one of fans' most common complaints by making a significant change to the game's unlock system.

The way things currently work is that players are initially given access to three character classes (out of nine), and additional classes can be unlocked either with gold (a currency obtained by spending real-world money) or XP, which is accumulated by playing the game. Weapons, perks, and other items for each class can be unlocked through the same means. These unlockables are not necessarily better than the defaults; the alternative character classes, for example, present players with different ways to play.