This game feels like an intriguing mix of fleshed out ideas from both the Red Day: Episode One mod for Serious Sam: BFE, apparently also made by the founders of the Timelock studio, and the original Serious Sam 4. There are both vast open spaces, that finally allow the game to show off handling hundreds of enemies at once, yet without being too empty to feel unnecessary or too big to get lost in, and a big variety of closed space encounters, both finely mixed together. While managing huge crowds is vital in vast open expanses, managing your own position is equally vital in those tight courtyards, streets and bunkers. It's easy to allow yourself to be boxed in if a mistake is made in the heat of battle, but the same is true for the enemies, and managing space to create bottlenecks for the ever-increasing crowd is a game of it's own here. Praise has already been sung by others for the scope, design and balance of each level, and it's easy to imagine how, despite ages old basic gameplay formula, virtually each encounter can be approached in a multitude of ways. With all due praise, however, this game currently suffers from the same techincal issues Serious Sam 4 suffered from at launch, such as uneven framerates, GPU underutilization (which can stay at 60% even during a framedrop even on a high-end system), and general lack of optimization. This is really sad, seeing how most of the similar poor performance issues of the base game have been fixed by now. However, there are rumors that more content, such as Survival Mode maps, is planned to be added to the game, along with performance patches. Let's hope the tech issues will soon be fixed.
..but we buy games here and not, say, on Steam, for preservation amongst other things. This is why this place was once called "Good Old Games" (hence GOG). Now, with this one, if IO servers get shut down one day (and people say precedents happened with Hitman Absolution already, didn't play it myself), we get a very scanty almost unplayable "demo" of a once good game. So, one may say "it's not a DRM PER SE", but even then there is really no point to buy this version of this game here, especially if you already have it elsewhere. What a shame.
