Recently I acquired MMF2 and the sources of each of Lake's Sonic fangames. I mainly used this to datamine the game and extract high quality in-game images, however, I now have a much more significant use.

But before we begin, all the stuff you'll need: MMF2 and all of it's plugins (Can't tell you where to acquire these but just search for them on the internet). Sonic After The Sequel Source (https://drive.google.com/file/d/0Bw7vgPrOLeTHRlk3U1liSjl3U1E/view?usp=sharing)

Thanks to Burnsy for helping me over the past few days with getting to grips with MMF2, and for also giving me the idea to try my method of level loading.

Once you have MMF2 up and running, and you have the source downloaded, open up the source in MMF2. You should see all of the game's folders, each one corresponding to a menu or a stage.

Our goal is to create an exe that loads up the level we want to practice or IL immediately, without having to fiddle through all of the menus and debug to get there.

Find the level folder you want, in my case, it's "Castle Zone Act 1" (Moon Mansion Zone Act 1). Drag and drop this folder to ¤SECOND¤ in the list, ¤AFTER¤ "Options Screen".

Now navigate over to "Run", then "Build and Run". Save your exe in a place you want and give it a name you'll remember i.e. the level name.

Once it's done building, run the exe. It'll take you to the Options Screen so you can configure everything you need i.e. resolution and gamepad settings. After that, you'll immediately be taken to your level!

Good luck and enjoy your IL's!

There's a small extra shortcut you can give the .EXEs if you are doing Sonic ILs in the default resolution, like me: drag the folder above everything, including the "options screen". Cutscenes off is the only other option I use and it won't matter for doing ILs

That's how I made most of mine, but I know that some people want to adjust the screen resolution so it's actually visible to them, because a very small window on a 1080P monitor is almost impossible to play on. :P