B good but not A worthy
Gameplay is ok but the missions are not much fun to play.
Balance for PVE it is quiet good balanced but PVP need some finetuning and not such stupid stuff like what they want to change for interceptor (moon will be out of balance after that change). Mostly stuff like missing recoil or to high recoil issues for some weapons or the location for Mars map capturepoints and so on.
AI not the most stupid out there but also sometimes way to easy.
Challenges: Destiny has some challenges that can be hard but never unfair so thats what helps a lot to play it for some hours.
Story: Ok the storytelling is nice when it comes for storymissions but between them the lore is nearly not available.
PVP: Very well balanced in the beta except the autorifle issue (the autorifle is way to powerful in the current state as it's accuracy is way to high for all ranges so there is no need for skill for it)
Controlls: I hate console controlls for FPS! Maybe for a third person shooter but not for a FPS. Thats just the worst way to play a FPS ^^ I have nightmares of the way I need to aim to hit my enemy XD Give us the precission of mouse and keyboard controlls pls ;)