Typical FPS kill-a-thon with not much brought to the table.
In First Encounter, it is a rather generic FPS adventure that has our titular hero roaming through Egypt while blasting down extraterrestrial and undead villains alike who try to stop you. There's a pretty good range of enemies like headless suicide bombers chasing after you or scorpion men equipped with a gatling gun, but one thing's for certain, they do come after you relentlessly. Waves and waves of baddies will come after you as you shoot them down with catlike reflexes and hope you don't get blown to bits by your rocket launcher. It's almost like you have to catch your breath every time after you go through a vicious wave of 300 skeleton beasts charging at you. Perhaps it wouldn't be a bad idea to stock up on Mountain Dew or whatever caffeinated drink you prefer because there's no shortage of endurance killing sprees throughout the game.
I don't like is the fact Serious Sam: First Encounter is a very shallow game. There's nothing new or original that can be found. You got the same generic weapons found in every FPS game, ranging from your standard combat knife to your always trusty rocket launcher (to give credit, Serious Sam does have a fully-functioning Civil War cannon as a weapon). Also the pacing is cookie-cutter ridiculous as every level follows the same pattern. Kill every enemy that comes in your sight, restock on ammo and health, repeat. Never once did the game pull a 180 where the unexpected happened and I was thrown off guard. This unfortunately puts the game's difficulty off balance. It can be hard and frustrating trying to survive an onslaught of enemies in waves, even on normal, but the game somehow throws you a bone and gives you full health and ammo without even having the need to conserve your ammo.
Speaking about shallow, look no further than the title character himself. Serious Sam is nothing more than a Duke Nukem knockoff, but not as vulgar or obscene. You almost want to cringe when you hear Sam spout off some corny one-liners in the most goofy-sounding badass voice.
Once you beat the Egyptian levels, that's it. I mean there are also the co-op and multiplayer modes you can take a stab at, but good luck finding others to play with you.
I never played the original Serious Sam games, but I'm positive if you already own or play them, then you can just ignore the high-def editions.
I wouldn't recommend Serious Sam HD at all unless it was dirt cheap on Steam or at the bargain bin at your local Gamestop. I was able to score both the First and Second Encounter versions on Steam for a low price of $3.99. Anything higher than that and it's not worth your time and money. The only satisfying value about Serious Sam HD: The First Encounter is that fans of Doom and other old school first-person shooters will get a kick out of this one.