Once again, once finishing a level in Story Mode, Free Play Mode is unlocked. In this mode, you can select any Character that you have Unlocked at the time, and play through the level with them.
The main draw of this mode though is completing the game. Each level contains 10 Minikit Canisters to collect, requiring many of the abilities that you just don't have access to in Story Mode. Collecting all 10 will complete a Minikit, a type of Ship or something similar, as a reward.
The Red Brick returns as an extra collectible in every stage, now also applying to the Prequel levels. Collecting it will unlock a new Extra for purchase in the Cantina.
As always, I suggest completing the Story Mode completely before starting on Free Play, as you unlock pretty much every character you need to complete the game. The two characters you need are a Sith and a Bounty Hunter, of which only one is unlocked through Story Mode, a Sith (Darth Vader in VI-5). As for the Bounty Hunter, Princess Leia (Boushh) is no longer considered a straight-up Bounty Hunter in Free Play, so you'll have to buy one from the Cantina, I suggest either of the Fett's, Jango, or Boba. I also suggest collecting at least the Red Brick for Invincibility (in IV-4), the Minikit Detector (in V-6), and at least one of the score multipliers (x2 is in IV-6). While there isn't a Free Play True Jedi total anymore, making sure you have enough cash to buy everything is still important!
The different types of Characters are:
Astromech: Astromech Droids are the more Useful type of Droid. They have a Stun Baton that can stun other Droids, and have the ability to activate Astromech Panels. Astromech Characters include R2-D2, R4-P17, 4-LOM, IG-88.
Blaster: The most abundant type of Character, these guys are excellent at long-range combat, being equipped with a Blaster of some sort. The biggest ability these guys have is the ability to Grapple from Grapple Points. Blaster Characters include Padme Amidala, Princess Leia, Han Solo, Luke Skywalker (Episode IV Versions), Lando Calrissian, etc.
Bounty Hunter: Bounty Hunters are slightly better Blaster characters. Along with everything a Blaster Character can do, a Bounty Hunter also has access to Thermal Detonators, allowing the ability to blow up Silver Objects. They can also use Bounty Hunter Panels quite easily. Bounty Hunters include Jango Fett, Zam Wessell, Boba Fett, 4-LOM, Greedo, Dengar, etc.
Boxer: Boxers forgo the normal weapon, instead opting to use their Fists. It works, as they can take care of Enemies fine, however they don't have much else going for them. Boxer Characters include Lobot and Bib Fortuna.
Droid: Droids are downright useless. They simply are. That's it. Droid Characters include Gonk Droid and PK Droid.
High-Jumper (I-III Only): High-Jumper characters can jump higher than other characters. Allowing them to access places others can't reach. In this game, this only applies to the Prequels, as LSWII did not have High-Jumpers, in the OT they will simply have a standard Jedi/Sith Double Jump. High-jumpers include Jar Jar Binks, General Grievous, etc.
Hover: Hover Characters can Hover as either a Second Jump or as a replacement for a Jump. Useful for crossing larger gaps. Hover Characters include R2-D2, R4-P17, Jango Fett, Boba Fett, etc.
Imperial: The Imperial Army gets their own class. While generally being Blaster characters, Imperials also have the Extra aspect of being able to use Imperial Panels. Due to Order 66 Schenanigans, Clone Troopers also apply. Imperial Characters include Darth Vader, Stormtrooper, Clone Troopers, Grand Moff Tarkin, etc.
Jedi: Jedi are the warriors of Peace and Justice in the galaxy, or were until they were effectively wiped out. Jedi use a Lightsaber as their primary weapon and have more acrobatic ability than basically any other character. They can also use the Force, so a plus for them. Additionally, Jedi now can use a Jedi Mind Trick on Troopers, due to their weak mind. Jedi Characters include Obi-Wan Kenobi, Anakin Skywalker, Qui-Gon Jinn, Luke Skywalker (Episode V and VI Versions), Yoda etc.
Physical: Physical Characters are Characters that have weapons and don't fit into any other category. They generally don't do much either. Physical Characters include Gamorrean Guard.
Protocol: Protocol Droids are rather useless, slow droids besides one thing. They can utilize Protocol Panels. That's about it. Protocol Characters include C-3PO, TC-14, 4-LOM, and IG-88.
Shortie: Shortie Characters are shorter than others, giving them the ability to access passages that others cannot. Shortie Characters include Anakin (Boy), Boba (Boy), Wicket, and Ewok.
Sith: Sith are the opposite of Jedi, and as such, share many similar Characteristics. In addition, Sith can use the Force on Dark and Red objects, while also being able to use things like Force Choke, or Force Lightning, depending on the Character. Sith Characters include Darth Vader, Count Dooku, Darth Maul, and The Emperor.
Walker: Walkers are Characters who are either useless or effectively useless! They can have Weapons, but not ones that do anything. Walker Characters include Jawa.
Guides are found here: