Boner doesn't put up a challenge at all. To defeat him, Tim only needs to ram into him 6 times to complete the level. The boss's only protection is two bones (each one of them doing 1 hit point of damage) which however are positioned way to high to hit Tim if he doesn't jump.
Other than that, Boner will simply walk from the right to the left side of the room, turn around, jump off screen and fall back to where he started from. This pattern repeats indefinitely.