Here are our Unlockables for Enter the Gungeon on Xbox One. The most trustworthy items get the most 'thumbs up' from our users and appear nearer the top!
In addition to the main characters available from the start, there are two playable characters you must unlock.
The Bullet – Spare five Red-Caped Bullet Kin. These are rare, smaller bullet enemies wearing red capes. They won’t attack you. If you encounter one, clear the room of other enemies and then wait until the red-caped bullet disappears. Do this five times to unlock The Bullet.
The Robot – First, befriend Tinker. Then, give him the requested items needed to repair the Chamber 2 elevator. You can do this across multiple runs. (Note, to get the Master Round, you’ll need to defeat the boss without being hit.) Once the elevator is repaired, you’ll be able to enter the elevator shaft and find the Busted Television. Take this item to the Blacksmith in Chamber 5, but be careful, because you’ll drop the Busted Television whenever you roll. If you successfully get the Busted Television to the Blacksmith, you’ll unlock The Robot.
To unlock the Blockner secret boss battle, you need to find the secret room in the Hall of Knowledge (the tutorial area). In the room after Manuel leaves, go to the room of the left and use a blank on the cracked wall. Inside the secret room, you’ll find the Old Knight’s Helm and the Old Knight’s Shield. Defeat Ser Manuel and then talk to him. He will tell you about Blockner. This makes Blockner appear in the Black Powder Mine.
(Note: after you defeat him, his ghost will appear as an NPC in The Breach and he can also appear as a mini-boss.)