It looks pretty good. Below, as you already know, the words in parenthesis are optional.
영화를 보는 대신(에)책을 읽을 걸 그랬어요.
공부하는 대신(에) 게임(들)을 하는 데 다 시간을 낭비했어요.
And below, "했서" is the past tense, but I think the present tense is what is appropriate here :
...시간을 낭비했기 때문에... (also a present state, "here you are in the present having wasted time on playing games...")
Unfortunately, I do not understand your question regarding "위에". Perhaps you can clarify a bit.