Hello,
Thank you for your feedback. We did quite consciously decide to deviate from the original game in a number of ways in order to make the game, we believe, more fun. There was a lot of discussion on the dev team about invulnerability in particular. We think one reason 4.2 had such poor player retention was because the old invuln system made many weapons feel unrewarding. You could load 10 bullets from an automatic into an enemy and maybe one or two would count. Many players would confuse this for bad hit reg. So we altered the invuln system with the knowledge that a few hardcore GE players would dislike it, but many more players would find the game to be more fun.
If you find 16 players on Bunker too hectic, then I would recommend joining a smaller server. We give servers the freedom to largely do as they please. That means players need to use some discretion and understand that any server they join may not have an optimal experience.
We've gone to great lengths to optimize the game, but please understand that we're stuck on an outdated game engine and there's only so much we can do. In terms of graphics we're trying to compete with other modern games, so there have been a lot of visual upgrades since 4.2. That comes at some cost to performance, but on the bright side we get fewer comments such as "GE:S is so ugly I wouldn't touch it with a ten foot pole." Game development is all about trade-offs.
You may disagree with our decisions, but we hope you'll still appreciate that many people have donated their time to create this game.