It takes some time to get used to game mechanics, like on first I didn't notice gears or I totally forgot that gears make you heavier, so I was trying to escape from enemy base with 36 gears on my back lvl 1 😅.
Anyway, the game doesn't feel monotone because there's a bunch of different enemy types, which spawn in different patterns. Beside the map, textures, music and sounds(except high-pitched on pickup) are making the difference in an awesome manner too. Also really liked the implementation of risk mechanic.
Maybe would've liked to be able to change volume in-game and have less ammunition from the start, so that buying it makes more sense and the game is more risky from the start, but those are actually trivial matters, not worth putting even a star off.