When I was small, I played with my Lego.
Can I check why L'imparfait should be used? I understand that l'imparfait is used for repeated actions or habit in the past. However, the English translation doesn't seem to reflect that.
Within the context itself, I can argue that
1 - When I was young, I used to play with my Lego (as a habit) - Quand j'étais petit, je jouais avec mes legos.
2 - When I was young, I played with my Lego (one off event, which ended in the past) - Quand j'étais petit, j'ai joué avec mes legos.
Thanks lots