Blizzard's upcoming hero shooter Overwatch has had a lengthy run in closed beta, and core features are still being changed.

The latest modification is a new character progression system, replacing the developer's two prior attempts at creating one.

Originally, character progression worked similarly to other Blizzard titles like World of Warcraft and Heroes of the Storm, with characters unlocking new abilities as they accrued experience points.

According to game director Jeff Kaplan, that system was ":super powerful and broken and unbalanced," so it was replaced with a system that unlocked cosmetic items as characters levelled up.

But even that system "[encouraged] the wrong behaviour," making players stick to a single character instead of switching amongst multiple heroes.

Kaplan says the new progression system is "light, cosmetic and almost [like] the game thanking you for your time in it," with little bearing on gameplay.

The system will debut in Overwatch's next round of closed beta testing in mid-January.

Overwatch is due for release on new-gen consoles and PC by the end of June 2016.