That's how I taught Part 23 twins: The 'single' engine was split into two packages, somewhat like a V8 engine. A failure would most likely affect only a single package, leaving the other half still running.
Just like a V8 with one dead bank. Might be just enough power to drive along a level road (if it was a big enough capacity V8), but probably not enough to go uphill, nor enough to tow a heavy trailer or with a the handbrake on. Particularly if in the mountains. In the Part 23 twin, maybe enough to maintain altitude (if a big enough twin - think >6000lb etc), but probably not enough to climb. Bad luck if heavy, draggy, high density altitude.