One thing I love about A.I.R. that isn't mentioned anywhere (other than the comments in the script files) is the amount of quality of life that's been added. The door switches and blocks in Sandopolis? They don't take as long to push now. The Guardian boss in Sandopolis 1? It will slide against the ground after you hit it so you can push it toward the quicksand faster. Ever accidentally step into one of those ring transporters in Death Egg that often take up more time than they save? You can jump out of them now! A few other features I love include the ability to have the music stay the same (no speed up) when you transform, the option to mix and match the prototype/final tracks to each Act, Sonic 1&2 boss music in Sky Sanctuary for their respective bosses, the ability to keep your current shield after finishing a Zone, and the more engaging Angel Island 2 bombing section that require you to jump over the bombs instead of just having you hold right the entire time. I also should note that a ton of smaller (mostly visual) bugs found in the original game have been and are still being fixed thanks in part to others contributing to the project, like certain object sprites using the incorrect palette line, Lava Reef 2's glowing crystal palette cycle accidentally using duplicate colors, making the crystals look less detailed, and behavioral bugs like characters falling right through the anti-gravity platforms in Carnival Night when taking damage.