Ratchet & Clank is an action-adventure game that takes place on many different planets, with you controlling Ratchet the majority of the time. You have your standard movement, such as jumping, but Ratchet can also strafe left/right by holding down the L2 button. Ratchet has access to a melee attack, which is a wrench, but while strafing using the button above, using the melee button will make him throw the wrench.
In addition to his melee attacks, Ratchet can also use a variety of weapons throughout his adventure. These weapons are usually bought from the Gadgetron vendors you will find throughout the planets, but a few of them are gotten through other means. Weapons you purchase require bolts as currency, which can be gotten from defeated enemies or by destroying crates. All but one of the weapons have limited ammunition, which can be replenished either at the vendor or from breaking open ammo crates scattered around the areas you explore.
When you begin the game, Ratchet only has 10 health, which is displayed at the top of the screen. As you kill enemies, you will earn experience that is shown on the bar underneath your health. Upon reaching a certain threshold, you will level up and all of your health will be restored; leveling up will grant you an addition ten health to your overall total. The maximum health you can have for Ratchet is 200, which will likely require you to play through Challenge Mode at least once.
Note: No matter how much health Ratchet has, you only get a maximum of five health when playing as Clank during his own sections.
One of the major reasons for playing the game will be the weapons that Ratchet gains access to throughout his adventures. As previously mentioned, you can purchase a majority of the weapons from the Gadgetron vendor, which is a small, blue box with a "G" on it. There are a few weapons that require other means in obtaining them, but you will mostly be buying them using the bolts you acquire.
Every weapon you get will start out at level 1 and as you use it, the weapon will gain experience, similar to Ratchet himself. As the weapons level up, they will grow stronger and upon reaching level 5, they will usually gain an additional property. For example, the Sheepinator becomes the Goatinator at level 5 and the animals you create from the enemies will now attack any living enemies in the vicinity.
When you reach the second planet in the game, Novalis, you will learn about Raritanium. This precious mineral is important to you, as it can be used to buy mods for your weapons. These mods can only be gotten at the Gadgetron vendors, where you simply press Square to access the screen. Every single upgrade to a weapon will only cost a single Raritanium and more mods will become available as you level up the weapon. In addition to normal things like increased ammo, getting all of the mods around the orange hexes will unlock Mystery Mods, which are special enhancements.
Not far into the game, you will acquire a gadget known as the Trespasser. There are special doors that are locked and can only be opened by using the Trespasser, which will require you to rotate lasers to hit special nodes. Once all of the spots are covered, then you will finish the puzzle. While the puzzles will start very simple, new mechanics are thrown in to make them especially challenging.
Puzzle Difficulty: The puzzles for the Trespasser are tied to the in-game difficulty, meaning one solution you find might not be applicable if playing on a different difficulty.
Later puzzles can get particularly nasty and difficult, as you are introduced to "walls" fairly on. These "walls" will block any laser, making it challenging to hit the nodes on the outside edge. The obvious method of aiming one of the lasers might need a different location because of these "walls." Later on in the game, one more mechanic is introduced, which is the ability to turn a ring on and off. Sometimes, you might even need to turn off a ring with lasers in order to solve the puzzle.