Real Score (Because GS does not allow decimal scores now) - 7.5
Ground Zeroes is very entertaining while it lasts, there's no denying it, but it's not worth the price of admission as it stands. Is it a great form of showing the new mechanics awaiting ahead for the real MGS V? Sure. But it's not more worthy than $20 when you can buy full games for less than that.
The version reviewed here is the PS4 version, and as a technical showcase of what the new gen can do its Ok'ish, nothing groundbreaking. There's great lightning effects, some very good textures and it runs at a silky smooth 1080p/60fps. However, when compared to the PS3 version (wich I also checked out) there's really not much difference besides the resolution. Overall it's still a very good looking game by todays standards but I doubt it'll stand the test of time in the long run.
Gameplay wise though, its a marvel. Snake's animations are fluid and responsive making him very easy and intuitive to control. The gunplay is serviceable but there's a new mechanic that slows down time when spotted wich makes the game fairly easy (although I believe it can be turned off in the menu options).
Ground Zeroes comes with a main mission that serves as a prologue to Phantom Pain (the proper MGS V game) and four other side missions with another extra mission exclusive to each platform (Xbox and PS). The main campaign is very very short and it doesnt add much to the MGS storyline but its still very interesting to follow through, especially the last cutscene wich will certaily shiver the weakest minds. Kojima is trying to be more serious in the new MGS and it shows. I like it.
The exclusive extra op for the PS4 plays with nostalgia and it was the best thing after the main campaign for me. Old time MGS fans such as myself will definitely appreciate the care put in this secret mission.
All in all, Metal Gear Solid: Ground Zeroes must definitely be checked out not only by fans but everyone that likes action/stealth games. However, due to its short length I would advise you to wait for a price drop or rent it/borrow it. Great experience.