I have had a P22 Walther for somewhere past 10 years. The only function problems have been ammo related. It runs great on most high velocity, 36gr HP, or 40gr solid point. Accuracy is good with Remington Golden Bullet, and excellent with CCI Mini Mags. Other brands are less accurate, but work well.
Tye biggest problem I have had with the little Walther is it gets me in trouble because when it goes along to the range I end up spending an extra hour or so shooting it addition to what ever else I took to shoot.
But, get ready for the "potmetal patrol" with their dire warnings about how terrible a gun they have never owned, or probably never shot is. The P22 has the Walther name, but is made by Umerex. They use a zinc, aluminum, magnesium, copper alloy called Zamac for the slide. Some of the early models with a steel piece that was attached to the barrel with a set screw had a problem with the slide cracking. Most often because the steel extension was miss aligned, and the Zamac slide slammed against it.
Fun little guns, and in my experience very reliable. Ended kerping a round count somewhere in the mid, single digit thousands.