It's not, it really isn't.
Or did you not see the over 20 page change log showing that they changed almost every single mission, enemy type, difficulty, boss, and playable character in the game? Most of which targeted toward fixing most of the complaints toward the game and adding new content we didn't even ask for.
Also, considering it's had over 4 years to prepare, I would have thought that they would have all of the new features ready to show off and not just show one aspect of the changes while only vaguely mentioning all the others.
That's kinda unbelievable.
One of the most basic complaints is that you can't turn off the bloody palace timer.
Lmao. I read the entire change log, and it's like I said- most of these changes to every little part of the game are values you can go in and change in a few minutes. Lock-on and Vergil's Bloody Palace are the only impressive technical achievements in that list. I don't think you even need to be a game developer to understand this isn't a great deal of work.
So, let's compare the workflows.
DmC: DE modifications
Enemy remixing (including Vergil's Bloody Palace): Check existing wave locations and spawn points, change enemy IDs and locations (X,Y,Z) and test the differences. Reiterate until it's good enough.
Estimated time: 1 mission per day if you really want to iron it out.
Time adjustments like parrying: Find range for the specified action, narrow or broaden as much in either direction as necessary. This is only ever two values, the start and end points. You're just typing two numbers and checking if it feels right.
Estimated time: all adjustments could be made in a few days, but it would take a week or two to play test from scratch (this may or may not have been done- they could have just gone on without feedback).
Additional angle dodge: Add 1 to allotted consecutive glides and adjust cooldown time after third dodge to be longer than the first two.
Estimated time: A few seconds, with a day to test if you're a good girl/boy.
Adjustments to boss AI, addition of lock-on, additional costumes and never before seen cutscenes (they already existed, at least the mocap): This stuff is actually hard as it involves adjusting a multitude of interdependent values, adding UI and messing with existing control modifiers, as well as creating new artwork.
Estimated time: Probably a little over a month with all cylinders pumping.
Some impressive stuff in there that took more time than the rest, but most of the 'wow, gee that's neat' features could have taken moments if they didn't care to playtest it extensively.
DMC 4: SE modifications
New model for Vergil, especially cutscenes: This has to be built from the ground up with several design considerations as it's to be used in new story content. It can't just be a tacked on costume, it's needs to evoke classic Vergil in an upgraded realtime rendering engine without stealing Dante's aged visage.
Estimated time: A couple weeks to build a character model for cutscenes and a separate one for gameplay.
Animations for Vergil, Lady, and Trish, both ingame and cutscenes: This requires not only the grunt work of actually creating the animations, but designing them from scratch (especially the choreography for cutscenes). There are dozens of decisions to be made before the animation can even begin, and many times new models are created just for the sake of a cutscene (Vergil's cloak, for instance). Each attack must be planned around the existing gameplay and designed to work well and provide a reasonable challenge before you touch a single limb, and even then you have hundreds of individual animations to create from scratch as they need to be modern and you couldn't transfer the animations from DMC 3, anyway. The particle effects alone would consume a massive chunk of this workload.
Estimated time: Too much time. At least a month for the cutscenes and one month each for every character if we're being absurdly optimistic. Making sure it all works fluidly and looks right for the individual characters is tough even when you're able to reuse one or two things from Dante.
The actual combat for each character: In tandem with the animators, you adjust the force, hitboxes, distance traveled, invincibility frames, leg height animations, and a few other things for every single frame of animation, and with each iteration it's possible you'll both have to redo a lot of work (including removal and replacement of a previous day's work because it needs to be iterated heavily). There's a lot of trial and error and testing that needs to be done for every situation to make sure it plays right and feels like a real improvement after 7 years, while still fitting within the games existing mechanics.
Estimated time: I honestly don't know. For each character, over the course of the entire development, this has probably been the focus and has required most of the development resources. I'd say several months if you lumped it all together.
Reactions to additional abilities that weren't accounted for vanilla DMC 4: The effects of Trish's lightning, Vergil's summoned swords, and Lady's explosive loadout could all have properties that weren't shared by Nero or Dante in the original game. As such, each enemy and boss needs a way to respond to these new abilities. Vergil's raining swords are a perfect example as they appear to freeze the enemies as they are stunned, as well as Judgement Cut End.
Estimated time: This could have taken a couple days, honestly, since a lot pieces are already there. Deciding to actually have these effects probably took longer, and testing them longer still. Maybe a week or two if I'm optimistic.
I could go further with the additional costumes for each of the four characters who have them (Gloria was already there) and the adjustments to autosaving and Proud Souls, but I think you can get a rough idea of those from the DmC changes that are similar. So yeah, I'm sorry, but I feel like it's not even comparable, and I haven't gone all that in depth despite this wall of text. I'd like to be more succinct, but creating games is a complicated process that shouldn't be underestimated, and it always hurts developers when outsiders make uninformed assumptions of what it takes to change or add to a game. The design and testing process alone are invaluable and unquantifiable, outside of the actual grunt work.
TL : DR Modders could have (and did) make most of the changes introduced in DmC: DE. I'd like to see any modder in their right mind try to add what DMC 4: SE is offering without losing their mind and soul in the process.
