I've tried to do some glitch hunting. Haven't found anything useful yet but maybe someone can come up with something with these. I've also made videos showcasing them.

You can push guards around after stunning them. You can also climb on guards by getting a bit higher than them.

You can climb many objects. You can also push guards up the same objects but I wasn't able to get a guard on the green recycling bin, since it requires more precise movement.

This is the only area I've found where you are able to do this. You can also move around on the platform. The door seems to break once you do this.

Probably the most interesting glitch. By getting the bomb to fall under the map once it keep spawning it there. It also explodes instantly after a bit. You can fix it with a platform or a ramp.

You can get the boat from one of the garages nearby. You are able to swim around for a bit until the counter hits 0

By jumping out of the boat before the cutscene you don't get the rocket launcher.

You can freeze the game by starting one of the side missions before the cutscene.

This isn't a glitch but you can shoot the valves and they spin. It doesn't seem to activate anything.

Cool finds, thank you for documenting these. I'm pretty sure the valves are for a side mission on that level but can't say for sure since it has been a while.

Years ago, I had a theory that if subway level is entered early, subway mission begins therefore skipping everything before that. I really want to test it, maybe by using CE or some save file fiddling.