This isn't mine, but I wanna share it cause it is neat. It is by a user on discord named big_trov (or at least that is what I am told). It is early but looks to recreated SS2 in SS1.

https://youtu.be/ah2RkLABBng

https://youtu.be/F3DIGCAZcvc

I also had my own idea of doing SSR in SS1, at least the levels. Which shouldn't be too hard I don't think. Outside of the levels probably.

Would like to do SS1 or SS2 to SSR but no mod tools exist yet for levels.

And people have tried SS1 to SS2 but all those projects were never finished