The initial prologue mission is played as Darth Vader who discovers Galen “Starkiller” Malek as a child, and raises him as a secret apprentice (even secret from the Emperor). The rest of the game is played as adult Starkiller. Vader tasks you with helping hunting down the last of the remaining Jedi after the purge at the end of The Clone Wars saga.
Since Starkiller's existence needs to be a secret, you have to kill Stormtroopers as well as Alliance soldiers. It doesn't seem to make sense, especially after the twists happen. I'm not convinced it really ties well into the film's story given that you'd expect Starkiller to be referenced (his presence can't really remain a secret, given how powerful he is).
Starkiller is very powerful, the most powerful Force user I've seen depicted in the films or games. The initial missions puts a focus on grabbing and pushing, so you will be tearing through enemies, launching them about - putting the rag-doll physics to good use. There's many objects to throw about, causing havoc and crushing enemies. These initial sections are very fun.
As you play, you will unlock new force powers like lightning. However, the difficulty ramps up, so you won't feel indestructible. When you level up, you can assign points to increase your abilities. You get points in 3 categories, Talent, Combos and Power.
You can block to deflect blaster fire, grab objects/enemies, slash with your lightsaber, Force Push, and Force Lightning. You can chain Force powers onto your basic slashes (when unlocked) which do larger damage.
For grabs and Force Lightning, the game will auto-target unless you use the lock-on function. Either way, I found it often targeted something undesirable, leading to many frustrating moments.
You have a limited amount of Force, but it regenerates quickly. Health regenerates with every enemy defeated.
Some enemies can knock you down or temporarily stun you. These can be very frustrating because sometimes it is impossible to escape before they land the next blow. You can also be sent flying with the rag-doll physics, so sometimes are unlucky and be pushed down to the abyss.
Special enemies and bosses require Quick Time Events to finish off. These are very simple to complete.
There are power-ups in certain sections which give you powers like extra damage, health drain, or restore your Force or Health. Some power-ups are positioned awkwardly; they are floating above you so you have to jump to collect them.
The bosses were often very frustrating. I felt there wasn't much feedback to allow you to understand what was expected from you. The Jedi battles seemed inconsistent that there are times when they block you, but other times they have their guard down and yet your slashes don't seem to deal any damage. They can counter your Force powers but sometimes they seem to damage you, and other times there's a small Quick Time Event where you get the opportunity to damage them. So you never know if you should use a Force attack because you never know what the outcome will be.
The Star Destroyer boss is ridiculously bad. You have to zap a wave of Tie Fighters, and you definitely see how bad the targeting/lock-on is. Once you have defeated a wave; using the Force, you have to rotate a Star Destroyer to drag it to the ground. It is incredibly slow to do so, and for some reason, you have to point it towards you and perpendicular to the ground, before pulling it down. You won't have time to do it in one attempt, so you end up defeating 4 or so waves. It is slow, boring, and makes no sense. Furthermore, a few times, I was hit, then rag-dolled to the railing where I got stuck and couldn't enter the platform; leaving the only choice to suicide and start the battle again.
There's plenty of glitches in the game. From enemies failing to move, committing suicide, to sounds failing to play; meaning some sections don't have music, or limited sound effects.
The graphics are very dated too, but probably looked decent at the time of release. Force Unleashed often feels clunky and lacks the polish you'd expect from a major title. The difficulty is quite erratic, it is often frustrating, but there is some fun to be had in parts.