head to head
Drawful 2 asks more than Garry's Mod, and the gap is reads.

Reads · Bluff & Deduction
A party game of drawing weird prompts and fooling players with fake titles.

Reads · Light / Casual
Source-engine sandbox whose community modes range from building to social deduction.
Drawful 2 leans Reads (Bluff & Deduction); Garry's Mod leans Reads (Light / Casual).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Drawful 2
Drawing ability helps slightly on a phone screen.
Garry's Mod
Varies by mode; base sandbox is undemanding
Drawful 2 leans clearly harder on reads.
Drawful 2
Decoy titles target how your friends think.
Garry's Mod
Social deduction modes like TTT involve humans
Drawful 2 leans a little harder on variance, though the gap is small.
Drawful 2
Absurd random prompts shape each round.
Garry's Mod
Hidden roles and player chaos in popular modes
Garry's Mod leans a little harder on optimization, though the gap is small.
Drawful 2
Few systems to master beyond title phrasing.
Garry's Mod
Contraption building rewards systems knowledge
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.