OK I played this and, well, yeah, very very rough around the edges. The scripted scene where the Mercs bust out is where they are supposed to attack the Skaarj, right? They didn't, because I had already killed said Skaarj

I guess the triggers aren't placed right for that event. Also, the gameplay was really weak, and I am generally not a fan of a huge mishmash of weapons in SP (especially the UT Chainsaw, which is easily the worst FPS chainsaw in existence by a long shot). The Quadshot was overpowered, Pulsegun nearly useless, UT Rifle overpowered, ASMD nearly useless (against the bosses), etc. And there wasn't really much combat, except for the boss fight, which dropped me from 100 health and 100 shield to 16 health in about 20 seconds. I had to godmode the rest (and this was on Medium!). Pretty much impossible fight, there.
That said, I DID really like the visuals, and the idea was really cool. Also, good music choices, even if the boss music wasn't really fitting, that is one of my favorites. I liked the whole going back in time bit. I just wish the map was more polished and had more consistency in story presentation, gameplay design and balance, and weapon/item usage, etc. There were a couple bugs like Scrag mentioned, but those are overshadowed by the overall feeling of incompleteness. Also, while the textures were different between future and past, the placement of objects wasn't. Also, was that tower meant to be inaccessible in the past? I couldn't get back up there.