More playable characters

It would be amazing if characters like Master Splinter, April O’Neil, or Casey Jones could be unlocked and played.

More bosses and mini-bosses

Fights against villains like Shredder or Krang would be incredible. Even smaller mini-boss (Leatherhead, etc.) fights throughout levels would add variety.

A 4-player mode

Being able to have all four turtles (or characters in general) played at once would make this game even more fun for families and groups.

A real campaign mode

A longer story progression with stages would give players something bigger to work through.

Achievements and progression challenges

Things like defeating a certain number of enemies, completing levels with perfect moves, or special skill challenges would add long-term goals.

New maps

Locations like the Technodrome, TCRI building, or the sewers would be awesome environments to battle in.

Vehicles and powerups

Imagine temporary powerups where the Turtle Van, Battle Shell, or Turtle Blimp shows up.

More Foot Soldiers with better combat

It would be cool if they fought back, had different attack types, or appeared in larger waves.

Environmental elements

Things like mutagen ooze hazards or power boosts could add another layer to the gameplay.