Solid, reliable gameplay with a unique and engaging premise
The graphics are crisp, with the in-game environment very clean and the character models seamlessly blending into the background, even though the textures are not as realistic as other next-gen games (Understandable given this is one of the pioneering games). Still, the overall look and feel of the game fits the type of story and I felt that on some levels the graphics looked amazing. Character animation is smooth and free-flowing, although I did think that the cut-scenes lacked "oomph".
The sounds were done quite well. My only gripe here was that some of the gun sounds were not as impressive as they should have been (the bullseye, for example is one of the more lethal guns in the game... yet it sounded flat).
Gameplay was well balanced. The levels are exciting enough to keep you on your toes, and they offer enough variety that you don't feel any repetitiveness throughout the game. I did feel that there were too few monster types in the game, as you see hybrids from beginning to end. Additionally, the boss monsters were not that impressive or difficult (Angels are the toughest, followed by Steelheads (IMO). The last four levels are particularly hard, especially where there are flying Angels --- but it never felt like they were impossible to beat. I finished the two most difficult levels (Angel's Lair and Last Hope) after dying at most 7 times.
What's nice in gameplay is that none of the guns felt particularly underpowered. Each of them has its own strength and weakness, and you find them pretty well matched up against the individual creature types. For example, the sapper gun does very well against crawlers and leapers, the bullseye is the answer to slipskulls, etc.... My favorite -- the sniper rifle -- is a good solution to steelheads and could easily have been the most powerful weapon in the game, what with the slow-mo effect and all. What's good is that Insomniac probably realized this early in testing and decided to limit it with only 12 bullets at any given time and a short slow-mo period.
The game is long enough to give you bang for the buck (especially now with its lowered price). Replayability is bolstered by the presence of intelligence reports and skill points, and with superhuman mode and new guns unlocked after finishing the game on hard --- you have enough reason to go through all of the levels again.
All in all, this is a quality game that offers a very satisfying 20 hours of play -- no glitches at all throughout the 40 hours I spent on it (Hard and Superhuman) -- and I'm looking forward to the second installment --- I'm buying Resistance 2 in a week.