People that say Unreal Engine can’t mimic the Blam Engine “feel” have no idea what they’re talking about. Unreal Engine is very much capable of recreating the Halo gameplay/feel but it’s up to devs to nail the aesthetics, atmosphere and small details to really reach the high bar previous games set in terms of gameplay, movement, physics, sandbox items and overall mechanics. (Obviously haha) Unreal is great and will make the content creation WAY easier than learning and dealing with the in house and outdated Blam/Slipspace Engine.
