Hey this was great! I liked the inclusion of the upgrade system, it gave it a bunch of replay value.
There's a great amount of variety in the enemies and train cars to start, and it's really nice to see the polish of the box blowing up sound effects, camera shake, and how each enemy type has their own type of weapon.
The music really amps up the rushed, time critical feeling of train heist.
The one criticism I have is I think the time boost upgrade is counter to the fun of the game. When I got what is essentially infinite time I lost that thrill of trying to race the clock. All in all it was a really fantastic game!