Your circuit is missing decouple caps for every IC.
And you might get problems with switch bouncing:
Still convinced single sided is a good idea?
It will get very hard for you to get a clean ground without dual layer. (Even dual layer will be hard enough.)
Why are you using a local label to connect stuff to GND instead of using the power symbol multiple times?
You trust in hidden power pins for gnd/vcc connection. Make sure they are connected for every IC.