[mywittyname]

I think it's parody.

If Weird Al did a song about being stuck in an IKEA, it would be parody.

If SNL did a skit about being stuck in an IKEA, it would be parody.

If The Onion wrote an article about being stuck in an IKEA, it would be parody.

Thus, if Jacob Shaw makes a game about being stuck in a (fictional) IKEA, it seems like parody.

[TeMPOraL]

In all seriousness, there is one stark difference between a song, skit or an article and a videogame - the latter has two+ orders of magnitude of experience time. I'm not sure if it matters in any way for fair use / being a parody, but a 3-minute song feels different than a videogame that takes 3 or 30 hours to complete.