This week vs the Steelers is basically the season

[*ochocincos*]

I would consider this a must-win, but that's primarily because I'm expecting the remaining teams to be (much) more difficult to beat than the Steelers.

Bengals are in the hunt, so they need to win and hope for some other teams to lose.
The good news is 4 of the teams ahead or in the hunt with the Bengals (all the AFC East) play each other one more time, so there's guaranteed to be some more losses for at least a couple of them.

I'm pretty much expecting TEN and KC to make the playoffs and probably win their division.
BUF and BAL also likely make the playoffs, leaving just 3 teams between CIN, NE, NYJ, MIA, and LAC.
Chargers have a pretty easy schedule remaining that it's easy to think they'll also make the playoffs, but they have been notorious in recent years floundering in December.
I don't see Colts making it since they have to play PHI, MIN, DAL, and NYG.

So pull out some upsets against KC, TEN, and/or BUF, and the chances of getting back to the playoffs become (much) higher.