I loved Serious Sam 2nd Encounter (haven't played the first yet), as it blended a nice world environment with some frag fest gameplay.
But then Serious Sam 2 just brought out the comedy side too much, with a cartoony feel to the game, especially with those goofballs between chapters. Nice that there were some toys to drive and ride, but think the charm had been lost with the loony tunes approch. Still the Whitty Sam did hold it together - such as ringing up for one end of level boss.
If Serious Sam 3 is brought out, please go back to the more realistic world and less cartoony monsters (I think the extreem reds, blues and greens were what I found more off putting), and lets have more of a Sam 1 feel. But DO NOT cut out the Sam comments. Ringing up for an 'End of level boss', or a telephone box that has him chatting with himself are priceless moments in the game. removing these would be like asking someone to play Quake with a towel for a weapon.
Weird Quake parable