I am playing Serious Sam, the original encounter again. Time and again you scrape through an encounter gasping for health only to stumble across an inviting looking health pack sitting in the middle of an apparently unguarded area. Without fail, picking up that health pack will spawn a new horde of vicious mobs and the cycle repeats itself. I am talking about hundred of mobs here. My fingers are literally sore from mashing the WASD keys frantically. I am not talking about mindless button mashing here. I am talking about precision aiming while moving under extreme duress button mashing.
This could quickly become tedious and a number of Sam's subsequent imitators did fall into the tedium trap but Sam's combination of cleverly designed levels with lovely graphics (dated of course but still lovely) great monsters, powerful weapons and an overarching sense of humour all just work to keep you playing and entertained. In my opinion this style of game has never been done better, before or since.
The game is old school hard, seriously. You die a lot and the game would be absolutely unplayable if not for the quick save function. Quick save has gone very much out of fashion in favour of checkpoints and automatically regenerating health bars. It can be argued that quicksave breaks up the flow and encourages a tedious "progress by infinitesimal steps" style of game. Serious Sam shows however that a game designed with quick save in mind can still produce a totally compelling gameplay experience. Its encounters are so overwhelming, the odds so ludicrously unfair that even with repeated quicksaves there is a tremenduous sense of satisfaction to be got each and every time you survive an encounter