Ever notice how sometimes vaguely similar movies are released within a short time of one another? I suppose the idea is to piggyback on the publicity of the other movie.
Some examples (not an exhaustive list) :
Abyss (1989) vs 
Leviathan (1989) vs 
Deepstar Six (1989)
1492 (1992) vs
 Christopher Columbus : The Discovery (1992)
Volcano (1997) vs Dante's Peak (1997)
Antz (1998) vs 
A Bug's Life (1998)
Armageddon (1999) vs 
Deep Impact (1999)
Mission to Mars (2000) vs 
The Red Planet (2000)
White House Down (2013) vs 
Olympus Has Fallen (2013)
for your consideration :
Prometheus (2012) vs 
Small Apartments (2012)
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| Prometheus vs Small Apartments - So far my list of  similarities includes that they both have a pale, hairless character who is a "big fella" and runs around nearly naked (the skintight underoos of the Engineer in Prometheus and the white underpants of Franklin Franklin played by Matt Lucas in Small Apartments) |