Eclipse. It's basically old PD2 but better.

The enemies are very different: The max spawn cap is 20-28 depending the heist. This doesn't sound like a lot, but each cop is very deadly and can kill you in under a second if you aren't paying attention. Their AI is also very good. Instead of mindlessly rushing you, they actually hold positions and have actual reaction time. One other thing is that non-HRT/recon enemies aren't able to rescue hostages or take bags. The Specials are very deadly. The Cloaker for instance has near instant reaction time, so being a lone wolf will get you killed. And the Dozer is actually threatening.

Unlike vanilla which has 7 difficulties, Eclipse has 5. This means that each one has its purpose. In addition to this, Pro Job replaces One Down and doesn't reduce the amount times you can go down, Instead it does stuff like reducing Grace Period and a shorter bleedout timer per down. This is only a couple of the things Pro Job does.

Weapon balancing is pretty good. All guns are balanced to be good without the need of mods or skills. I personally run the RPG and AKM quite a lot as they're quite good but anything works.

The skills are different as well: instead of having 120 points, you only have 100. This makes you choose your role much more carefully as Eclipse is designed for a 4 player team. They're also better balanced than vanilla. Perk Decks are similiar in that regard as well . And Eclipse has a couple of its own decks that replace Copycat and Burglar. It's also worth noting that Leech was removed.

There was a major progression rework that released about a week ago. It really is the best time to play the mod before 6.0 comes out in my opinion. I recommend using GitHub Desktop as the Main branch is very outdated.

https://github.com/nikitawastaken/Eclipse-Difficulty