It will do fine within relatively short ranges.
What you fail to mention is something European hunters have known for a long time: More magnification, combined with a large enough objective lens, results in better "visibility," even at relatively short ranges. This is because many European countries allow hunting all night, not just in the normal "American" hours.
This is called the "twilight factor" (you can Google it) and is why many European "night scopes" had large objectives and more magnification for many years.
John has already given the best answer, twilight factor is what you want to look at.
This was positively demonstrated to me in South Africa. We were looking at a small herd of wildebeest just at full dark. I had a Leupold 3-9X40 set on 4X - which I figured was better due to a big 10mm exit pupil - but couldn't see the animals at all, the herd was just a big dark blob set against a slightly lighter sky. JJ Hack was my guide and said to turn the scope up to 9 power, which is only a 4.4mm exit pupil, but doing so immediately let me make out the individual animals. The twilight factor of a 4x40 scope is 12.6, √(4 x 40), a 9x40 scope is 18.9 √(9 x 40) .
I still couldn't make out the standard duplex reticle well enough to be comfortable with the shot, but that "higher magnification in dim light" thing was a real revelation.
Also, just to do the math, the twilight factor of a 2.5x20 is 7.
