Hello Yves, yes I understand your challenges but good to hear you wish to try something while improving your skillset.
Unity is licensed, while Unreal is free until you publish, we need to compare the pros and cons of them in terms of cost when publishing.
Both can export to all consoles, pc etc.
Take a look at the following games and get some ideas.
Horizon Chase Turbo = Very Lotus Esprit Turbo and Outrun
Crusin Blast = This is crazy pure nitro high speed
Hotshot Racing = Similar to Horizon Chase Turbo
Pure Chase 80's = This is a high-speed ride with more reaction than skill
80's Overdrive = Outrun this is 100% like Outrun
I think you need to figure out the branching paths and add 3D vehicles which fit in well with the road,
Perhaps make the road and ground 3D too? You can even have a mix of 3D and 2D if it works well.
We can take vehicle models and turn them low/lower poly 1/3 or 1/2. to give it a look.
This is something we would need to work on to get the look down and then start creating the elements.
How can we make it different?
Do you wish to keep the Authentic Outrun feel reproduced or go a little more exteme like Cruisin Blast?
I feel we should stick close to the Authentic Outrun feel with a few new elements which work well with it.
As the player reaches the finish line it could unlock items such as a radar detector, CB radio, and radar jammer.
Police could will be waiting on the side of the road so drive past slowly when you hear the alarm to avoid them.
This would add another element that still keeps it within outrun I feel.
We could add railway crossings, you need to beat the train to the crossing.
We could make each section a different country look, major landmarks and seasons, Japan blossoms.
France in Summer Eifel Tower, Moroco in Summer, Austria green grass blue skies and the alps.
Once we have the assets for one track figured out we can copy-paste it and replace the assets with grey numbered boxes
as placeholders for each track so as the artwork is complete you just need to replace the artwork pack.
This way you can continue testing the new tracks and make any changes until the artwork is ready to be replaced.
This ensures accuracy and speed in assembling this, you need to be able to add or remove any track section and move it around
in any order, look at how you have it set up you need to have this modular to give us the flexibility and not re-work everything.
Are you using a sprite sheet? This way each track asset can be placed on one .png otherwise with 3D you need separate elements
for each track section asset and be consistently named and numbered for instance France Summer Cloud Small = FR-S_Cloud_S.png
When this is presentable with a good menu and one or two working tracks, music and sound fx we could start pitching the game
to Lamborghini, publishers or even Kickstarter (after we figure out how much time and money it will take to complete.)
We would also require a contract to protect us both, too many projects and friendships turned sour because there was no contract.
Right now we would be putting in our time and effort and treating it like a hobby, but as we draw closer to pitching it and especially
releasing it we need a bank account set up in which all earnings enter and then automatically deposit the agreed % into your account and mine.
I have some handwritten notes which I need to type out, I also collected some royalty-free music which I think will really work well.
The artist of which can be contacted to request to do something similar to Outrun but that would be extra money.
I think the two of us could pull it off, if you focus on the game elements and putting it all together, I can focus on graphics, music, sound and UI
Looking forward to developing something great with you.