Normally, you'd be allowed to look at the entire circumstance to determine consideration if it was unstated. however, this contract contains some pretty strong

Normally, you'd be allowed to look at the entire circumstance to determine consideration if it was unstated. however, this contract contains some pretty strong clauses about the document being the entire terms of the contract. So maybe that would be enough to invalid it. But that would depend on the specific jurisdictions case law on contracts and then how the judges reading the contract. If this were my client and he got some kind of consideration, I'd tell him to treat it like a valid contract. Though I'd trying to poke holes in it during litigation. But litigation is losing 9 out of 10 times, even if you win.