僕はそのゲームを最初から最後まで見ていた。

。

I watched that game from beginning to end.

Literal

I [topic-は] that game [object-を] start from last until watching was.

~ていた marks a past progressive/continuous — 'was watching (throughout a period).' 最初から最後まで ('from beginning to end') is a common fixed pair using から...まで to span a range. Game here could mean a video game or a sports match depending on context.