The Flash upload worked but there are no messages from the sketch. This can happen if the ESP8266 does not receive enough power. Most USB to serial devices cannot supply more 100 mA @ 3.3V which is not enough for an ESP8266. Find a better tutorial that explains how to power an ESP8266.
The Flash upload works because the WiFi radio is turned off during this time. Once the upload is done, the ESP8266 turns on the WiFi radio and tries to run the sketch. If the ESP8266 does not receive enough power, it crashes before the sketch starts.