What I like about MGR is there's a variety and a pacing to it's structure, particularly the first four chapters. They don't overwhelm you with numbers, but it's just as offensive as any game out there. A fight with a few guys is then broken up with an stealth section in the dark, or a mini-boss, or ninja run escape or now you're a mini-gecko. The first four levels are long, but you don't really FEEL that length because they're always mixing up not just the enemies, but how you will encounter the enemies in a number of interesting ways. It never becomes a slog like NG2/3 where "ok here's a dozen guys, now here's a dozen more guys, now here's a dozen more guys, now here's a dozen MORE guys but this time with off-screen rocket spam fucking up the framerate", for eight hours of increasingly monotonous endless combat. It makes the game easily replayable, it leaves you satisfied after that incredible final boss, but it leaves you wanting more still.