Okay, here's what I would like;
Virtua Fighter 5 Engine
Make it play like a Sega game, not Capcom or Nintendo games. They can always make it more fast/over the top if they want to (worked in Fighters Megamix), but leave it with the same basic set up and button layout of B,P,K.
This also allows us to enhance the roster, since they could just throw in the whole cast of VF5 with very minor adjustments.
Roster
Unlike Sonic Racing, actually have characters that make sense and fit in well first and foremost, then put in the wacky characters. My personal choices would be
- Virtua Fighter Cast
- Sonic (because he would need to be in it in some form unfortunately)
- Fighting Vipers : Bahn, Candy, Mahler
- Eternal Champions : Larcen and RAX
- Streets of Rage : Blaze
- Golden Axe : Ax Battler
- Bayonetta
- Yakuza: Kazuma Kiryu and Goro Majima
- Last Bronx : Yusaku and Joe
- Shenmue: Ryo Hazuki and Fuku-san (as the training dummy)
- Dude from Altered Beast
- Hornet
At this stage I wouldn't even mind if they just cloned Akira to make Ryo and changed his costume and voice, ditto to clone Wolf and make a Max from SoR 2 character or something (obviously as a last resort to bolster the roster).
Stages
They could do some cool things with the stages i think. Again, recycle as much as they can from VF5 to start with then:
- Rooftop from Shenmue 2
- Green Hill Zone (Ring outs into a Waterfall)
- Benten St. (With one wall being made of the street barriers and the other being police Riot barriers, complete with Onishima watching from a cop car)
- Fantasy Zone
- Aircraft Carrier from Afterburner (Ring outs off the side of the ship!)
- The Delphinus (ring outs overboard!)
- 777 Speedway
All with appropriate cameos of course, have Crazy Taxi guys, Outrun guys etc racing in the background of 777 Speedway, have the Panzer Dragoons around the Delphinus, maybe Space Harrier as well. On Benten St you could have the Virtua Cops amongst the Tokyo-to police as well.
