There are many special trophy achievements in "Silent Hill 2: Remastered Edition (SILENT HILL 2)", and Ruthless is one of them. The requirement to achieve this trophy achievement is to kill 50 enemies with a stampede attack. To put it simply Just beat him down and then stomp on his head.
How to get the Ruthless achievement in Silent Hill 2
Ruthless
Kill 50 enemies with a stomp attack.
When attacking enemies on the ground with R2, he will sometimes stomp on them instead of swinging his plank/steel pipe, which is randomly triggered.
Note that this cannot be completed with the chainsaw equipped, so if you need to unlock this trophy in [New Game+], be sure to remove the chainsaw.
The best enemies are bugs, as they all kill in one hit, and James tends to stomp on them most of the time.
Note: This trophy can be accumulated and does not have to be completed in one week