From Sega Retro
Hustle Chumy (ハッスルチューミー) is an SG-1000 and MSX game developed by Compile and released in 1984.
In Hustle Chumy players control a mouse named Chumy who needs to collect apples (and other food) in a sewer, avoiding other critters as he goes. As Chumy eats more food, his speed decreases, but his fireballs are given a longer range. Levels have varying layouts.
There are several types of enemies in the game, most of which can be defeated with fireballs.