DG2 improves on everything from the first game. The level design is just as fantastic. The towers can now get upgraded abilities and the new boost towers are really cool. You will also need to use more than just gun towers in order to get gold medals. One of the best tower defense games ever made.

Got with free games with gold and played for maybe 2-3 hours. Eh.

Worse than the original in every way.

Defense Grid: the Awakening was a brilliant tower defense game, but for some reason they were unable to replicate that brilliance to this second installment. Defense Grid 2 is worse than it's predecessor in every way.

Decently little tower defense game. Can be picked up for cheap or free nowadays, but I think it holds up well. Plenty of upgrades and options for defending your base. Nothing world changing but pretty good overall.

I think this is my favorite tower defense game ever. I can't think of one I like more, to the extent that I bought it on two systems and 100%'d it on both. Not typically a fan of tower defense, so it must be doing something extremely right.