This is the fan-made version often found on "WTF" gaming sites. Recent community updates for the itch.io-based versions (like those by Gurpreet Singh) have added:

Rocket League Sideswipe is the 2.5D mobile game by Psyonix.

Fast-Paced Matches: Games are two minutes long, making them perfect for mobile play.Simplified Controls: While easy to pick up, the skill ceiling remains high with advanced mechanics like gold and purple shots.Ranked Play: Just like the core game, Sideswipe features a robust competitive ladder for 1v1 and 2v2 modes.Customization: Players can still deck out their cars with familiar decals, wheels, and goal explosions. The "New" Viral Fan Creations

These clones use simplified "ragdoll" physics, making the cars fly wildly.

At its core, the "Rocket League 2D" concept strips away the complex Z-axis of the original Rocket League

If you are seeing "WTF" reactions or experiencing issues with text chat, it may be due to recent updates in the main game: "Savage!" is now "Brutal!":