The Sony U would be the better phone of the two.
For apps/games:
Most or all of the apps on Google Play support android 2.3 so that means you can download the majority of apps on android. Also, you would be able to run those apps/games without any problems since it has a 70% faster processor and twice as many cores.
For movies:
It was stated below that the HTC Desire C has a better PPI and resolution. That, in fact, is the other way around. The Sony U has a better PPI of 279 PPI compared to the Desire's 164 PPI. It also has a higher resolution screen with 854 x 480 compared to 480 x 320. This results in a more enjoyable experience when watching movies.
Also, it is stated below that the HTC Desire C does not have expandable storage. That is also a misunderstanding because the HTC Desire C DOES have it. It's incorrectly stated on the comparison between the two phones.
Without a doubt, choose the Sony Xperia U since it is better than the HTC Desire C in performing the things you mentioned above.


