One criticism I’ll give this game is the lack of a progression system. I KNOW IT’S 2004 AND THOSE HADN’T BEEN INVENTED IN FPS YET, but given the big difficulty spikes after the 12th level, it would have been pretty helpful to have some unlockable health upgrades or ammo attachments.
But that doesn’t really matter because the game technically gives you all the tools to beat each level, you just need to find them sometimes. Some missions will be clearly based around sniping, but if you didn’t go in with a sniper, there’s always one you can find while backtracking.
The difficulty spikes in question are the special forces soldiers and the fat boys. You can unload an entire magazine into one of them, and they still won’t die. I guess they thought the switch-a-roo meant “same enemy but with more health” unlike the Flood from Halo which was a completely new enemy type.