Spear of Destiny - Mission 2: Return to Danger is an expansion both developed and published by FormGen. Id Software, the makers of both Wolfenstein 3-D and Spear of Destiny had nothing to do with the creation of Mission 2 except for the making of the engine and the games its based off of.
Return to Danger features completely redone graphics for just about everything in the game, a brand new enemy type, and five brand new bosses.
Six weeks after the Spear of Destiny has been brought out of enemy hands, the Axis mounts a successful commando raid to recover it! After a bloody battle and narrow escape, it's taken to the Nazis' Secret Scandinavian Base, excavated from the solid rock of a fjord The fortress is said to be impregnable!
Your mission is to recover it a second time!
(Taken from the back of the box)
Gameplay in Mission 2 is largely the exact same as it was in both previous Wolfenstein titles before it. Where it differs greatly however is in level design. Levels are designed with more enemies in them, often times when entering a room you'll be given the task of clearing out a room of about 15-20 soldiers, give or take a little.
Levels are also much more harder to run through, or just beat in general. The way Wolfenstein 3-D handled its secrets was by push-walls. The push wall was a hidden piece of a wall you can push to reveal a secret, more often then not it was ammo, health or a weapon. Return to Danger uses the idea of the push wall a little differently. Instead of hiding just treasure or ammo. Keys and even exits to the following level (not just the hidden levels) are hidden in a secret location.
There's one new enemy that comes into play in Mission 2, and that is the Bat. The Bat in this game takes place of the mutants from Wolfenstein 3-D and Spear of Destiny. So although they may look different they play exactly like the mutants. The same goes for the new bosses in the game as well. Each of the bosses may be new but they're just copies of their Spear of Destiny counterpart, so Death Incarnate plays like the Angel of Death, Submarine Willy play like Trans Grosse, so on and so forth.