You could always shoot enemies until they died in 1 and 2, dismemberment was just obviously a much faster and efficient way to go about it. Dead Space 3 still had dismemberment, there was just usually enough ammo to where it didn't play as major a factor. The abundant ammo was balanced by the amount of enemies thrown at you at any given point, and that they were made much, much faster. It definitely changed a lot from the first two games, but it was interesting enough to be an enjoyable experience overall. In particular I liked the inclusion of the human enemies as using your dismemberment tools on them was fun and the times where you'd come across them fighting monsters was great. Honestly think it would have been my favorite game in the series if not for the Dragon Age 2 style asset reusage in the side missions. The ice planet is gorgeous, and the amount of variety present is pretty impressive outside of the side missions.