As implausible as it may sound, I have a long-standing philosophical disagreement with Serious Sam. He genuinely believes that the true essence of playing an "old school shooter" consists of partaking in a series of protracted arena fights situated in big empty environments which quickly fill up with more and more enemies; a rigidly mathematical design which in turn requires planning, trial-and-error and a considerable amount of ammo micromanagement to be handled successfully. I have non-trivial reasons to suspect that he is wrong, and would instead argue that classic shooter gameplay can be usefully defined as a much more leisured, freeform experience - in which enemies are certainly numerous but also spread out across well-paced encounters taking place in detailed and varied levels.
I also seriously disagree with Mr Sam on another question; namely the inherent meaningfulness of an "HD" remake of a game which was intentionally designed to look quite simplistic in the first place. As such, I would never have payed more than the lowly 3 € he offered himself for on Direct2Drive today. Good thing Serious Sam - quite apart from his apparent shortcomings as a philosopher - also happens to be a rather cheap bastard...