It was hot outside, so I just stayed inside and played games in a nice cool room all day.
It was too hot to be outside, so I just stayed inside where it was nice and cool and played games all day.
ーIt was hot outside, so I just stayed inside and played games in a nice cool room all day.
「外が暑かったので、一日中涼しい部屋にいてゲームをした」
in a nice cool room で「涼しい部屋で」
ーIt was too hot to be outside, so I just stayed inside where it was nice and cool and played games all day.
「外がとても暑かったので、涼しい部屋で一日中ゲームをした」
where it was nice and cool で「涼しいところ」
ご参考まで！
カナダ 
