I think maybe someone at Bioware was just feeling a little bit inspired by the Oddworld design motifs
![](http://vignette4.wikia.nocookie.net/half-life/images/b/b9/Headcrab_Standard.jpg/revision/latest?cb=20090527202722&path-prefix=en)
On the other hand, I've heard people say that the Headcrabs from Half-Life are ripoffs of the Paramites, but I honestly doubt it considering that HL1 only came out a year after Abe's Oddysee. It's definitely an uncanny similarity, I'll admit, but probably just a coincidence.