If Unleashed starts off a miniseries...

If Day and Night stayed in, I'd prefer alternate routes to open and close, like a Forest area having a giant flower open during the day swallow Sonic and him end up in an underground area after travelling down the stem, be closed during the night, forcing Sonic to locate a new route.

 

Sonic & Knuckles.

Swap out some of the mechanics that don't make sense for Knuckles (like the stretchy arms) and maybe add gliding and wall climbing to the mix.

 

Make the fights for the Werehog much less repetative, and much less frequent. Seriously, you can make a level with some good platforming in it, but no, we are met by ghoulies every damn turn, slowing the game down.

The idea of being able to switch between day and night is quite cool, especially if I had the choice to, or not to do it. Just as long as both 'time zones' are equally interesting, and levels in their own right, that would be superb.

 

need a game where you play as Metal Sonic for serious

 

Needs more Metal Gear Sonic, amirite?

 

Personally, I'm hoping the theme becomes the 2D/3D shifts, and they scrap the Werehog altogether. If any other characters have to be present, they should be bonus material, and play Sonic's levels.

 

Add Tails, different alternate paths and I'll buy it.

 

Wasn't this one by LOsT?

 

I think the general theme carried by a sequel to Unleashed would be world exploration and the 2D/3D perspective change.

 

There are definitely many locations to be explored for a sequel, maybe even going to different parts of existing ones. I'd prefer Knuckles for the action-y brawler stages since they just make more sense with him. Sonic should also incorporate day time platform stages akin to Arid Sands Act 3 from the Shamar DLC pack.

 

How about just Sonic Heroes 2?

Edit: With only team sonic.

 

If you can give me something of a Sonic and knuckles-esque game with Sonic doing runny stuff and knuckles beating the crap out of things, then I'd buy it.
But if it possessed an epic storyline like Sonic and knuckles and took place on Mobius (hint hint) then that'd make it better, eventough it'd be scrapping the existing unleashed world.

Also, yes, the idea of a 2D/3D split would be good, however a little more 2D would've been nice

 

Honestly if they just made a game like Sonic Heroes but only starring Sonic and Knuckles (No Tails flying sections though) that would be sick. You could switch off characters whenever you needed to. If you needed speed, then go for Sonic. If you need some platforming done, have to cross a gap, beat up some baddies, play as Knuckles. I think it would be sick.

 

I think the team play would have been a great way to solve the whole "lack of multiple routes/exploration" problem in Heroes, but it was handled terribly. Instead of "you could go this way as Tails, or this way as Knuckles, or this way as Sonic" but instead it's like "RUN RUN RUN switch to Tails to fly over this thing RUN RUN RUN switch to Knuckles to break down something RUN RUN RUN repeat"

 

Whatever the developers decide to do, should they pull a sequel, I want gameplay selection to be reminiscent of Sonic Adventure; hedgehog stages (being the main attraction) focusing on speed and platforming with there being a main level gimmick every couple of zones or so to spice things up, and variational gameplay such as beat-'em-up and/or emerald hunting being side modes. I don't like being forced to switch back and forth between two games.

To be honest, though, I just want a game that takes the ideas of the 2D games and tried to put it into 3D. You know, with end zone bosses, two/three acts per zone, collect all seven emeralds (not just "earn" them in different cutscenes) and be able to turn Super Sonic in normal levels, classic stuff like that. It'd be very nice to have an "Eggman's at it again" plot with him being the major threat in the game to break the trend of the giant monsters at the end of each game. I don't see it happening, unfortunately.