不过是一个文字游戏罢了。

It's just a pun.

It's just a play on words.

Source: Tatoeba

Sentence Composition

1 不过 bùguò
  1. only
  2. merely
  3. no more than
  4. but
  5. however
  6. anyway (to get back to a previous topic)
  7. cannot be more (after adjectival)
=2 是 shì
  1. to be (followed by substantives only)
  2. correct; right; true
  3. (respectful acknowledgement of a command) very well
  4. (adverb for emphatic assertion)
=2 是 shì variant of 是 shì
=3 一个 yīge
  1. a; an; one
  2. the whole (afternoon, summer vacation etc)
=3 一个 yīgè
  1. Combination of the numeral 一 (“one”) and the generic classifier 個／个: a; an; one
  2. same
4 文字 wénzì
  1. character
  2. script
  3. writing
  4. written language
  5. writing style
  6. phraseology

classifier: 個
5 游戏 yóuxì
  1. game
  2. to play

classifier: 場
=6 罢了 bàle a modal particle indicating (that's all, only, nothing much)
=6 罢了 bàliǎo a modal particle indicating (don't mind it, ok)