Belloq and the Nazis may also count given that Indy is tied up, surrounded by goons, his arch rival has the artifact they were competing for (again)... and he essentially 'wins' simply by closing his eyes as the Ark wipes everyone else out.
A pretty minor one, considering it lost to a good movie like Chariots of Fire, and was up against a major epic like Reds and well-received dramas On Golden Pond and Atlantic City. But of those films, Raiders had made a more lasting impact (on summer blockbusters, adventure films as a respectable money-making genre, Harrison Ford's bankability outside of Star Wars, etc.)
Spielberg losing Best Director to actor Warren Beatty (for Reds) is an arguable case. Those who support Spielberg note that, while Beatty is a respectable director with a decent career, Spielberg was at the height of his powers directing incredibly well-made action movies. However, this is refuted by some who find Reds to be a directorial achievement above all else (not to mention a labor of love that took Beatty years to get off the ground), and many cite his win (the only Oscar he ever earned in his long career) as one that was justified both in context and by merit. It would get worse when Spielberg lost the following year over ET (after which is when he started making serious Drama movies).
"Funny Aneurysm" Moment: As Indy speaks with Marcus while packing for his trip, Indy says "You sound just like my mother" as he dismissively speaks of the Ark's powers (which turn out to be very real). In Indiana Jones and the Last Crusade, we learn that Indy's mother passed away during his childhood, and his relationship with his father fell apart afterwards. And he grew to hate his father for being so obsessed with the Holy Grail, rather than focusing upon Indy.
Iconic Character, Forgotten Title: Upon its original run, the movie did not follow the "Indiana Jones and the X" naming scheme that sequels did, simply titled Raiders of the Lost Ark. However in later home media releases it was retrofitted, ie: Indiana Jones and the Raiders of the Lost Ark.
When Indy shoots the truck driver from the Cairo market, leading to the truck tipping over, the mechanism being used to tip it is visible.
When Indy and Marion escape the Well of Souls, watch the shadow of the rock he pushes out. It bounces off the ground, thanks to being made of rubber.
In a scene with otherwise impressive effects for the time, the brief shot of the Ark's fire rushing over the bodies of the Nazis is a pretty obvious-looking miniature.
The transparent partition that separates Harrison Ford from the cobra used to be this but, hallelujah, Uncle George found a constructive use for his digital editing powers.
Visual Effects of Awesome: The melting head. It may not look as impressive nowadays but back when Raiders came out in 1981, that scene was the most talked about out of everything else.
While some say Indy was inconsequential to the plot (even on The Big Bang Theory), without him, Marion (and the Headpiece) would have remained in Nepal, and the Nazis would have never found the Ark at Tanis.
Additionally, Indy is the only reason why the Ark was successfully brought to the United States. Even if Belloq and Dietrich had still opened it on the island and gotten killed without his interference, without Indy the Ark would've eventually been brought to Hitler by the next group of Nazis to come to the submarine base.
Indy also ends up bringing about his own survival when he decides, out of respect for the Ark, not to blow it up. Had he chosen to do so, neither he or Marion would've returned home alive, all the bad guys would've lived, and he would've failed in his mission of getting the Ark to the United States.