That makes it sound as though the store is in front of something else - perhaps another store, or in front of the alley, or in front of the stadium. When talking about something up the road from us, or ahead of our nose (since we orient directionally to what is in front of our face, behind our back, and to our left/right), we would say, "up ahead" or "ahead."
"there store is straight ahead" is an obvious typo. Duolingo is a tad inconsistent with how it marks a typo.
The difference between «Прямо» and “Впереди” is the same as it is between “Straight ahead” and just “ahead”.
Straight ahead means directly ahead, without any turns. While if you simply say “ahead”, that could literally mean anywhere in like 120 degrees of viewing angle in front of you.
«Прямо» is more of an adverb though. You can say “Прямо впереди» and «Прямо сзади». Which is “straight ahead” and straight behind. Although usually “Right behind” is usually used in English instead of straight behind. Theoretically, that english phrase doesn’t make any sense haha
In front would mean - «Спереди» As “in front of the house” - “спереди дома”. Something that is on the front side of something
In this case «Впереди» is used. As in something is “up ahead”, or “down the road”. You can’t say that “Gas station is in front”, but you can say “Gas station is up ahead”. Same thing in russian.