What does "he was equally game to slip into bit parts" mean?

Question

I was trying to understand this line – he was equally game to slip into bit parts, but couldn't. My best guess is that it's meaning something about universality and flexibility in acting. Could somebody, please, make this line more clear or rephrase it?

Nothing was too big or too small for Hartman. He stepped up as the main, one-off guest voice in episodes like “Brother From the Same Planet”and “Marge vs. the Monorail”. And he was equally game to slip into bit parts, including his turn as the weaselly State Department official Evan Conover in “Bart vs. Australia” and sleazy football expert Smooth Jimmy Apollo in “Lisa the Greek”. In “Burns Verkaufen der Kraftwerk”, Hartman showed up as Homer’s lowlife stock broker and as German plant manager Horst. Many of his performances could have merited a big name guest voice, but Hartman nailed them so completely and consistently that you almost didn’t notice it was him

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Answer 1

be game
To be willing to do something.
Sure, I'm game to go to the mall.
Vince is game to play basketball—why don't you go to the park with him?
(TFD)

I assume you can understand equally.

I couldn't quickly find a definition for slip into, but I see it as a figurative extension of the following:

slip
intransitive verb
5 : to get speedily into or out of clothing slipped into his coat

In this case, it roughly means assume:

assume
v. tr.
3. a. To take on (an appearance, role, or form, for example); adopt: "The god assumes a human form" (John Ruskin).
(TFD)

A bit part is basically a small role:

A bit part is a role in which there is direct interaction with the principal actors and no more than five lines of dialogue, often referred to as a five-or-less or under-five in the United States, or under sixes in British television.
(Wikipedia)

In other words,

He was equally willing to assume small roles (as he was willing to assume large ones).