Getting there
Overall, this is a big improvement over the original game. The graphics for the monsters & the scenes are better. The weapon graphics are "meh" - meaning simplistic, but clean.
Somewhere in the middle of the 60 waves is a balance point past which it becomes very difficult to ride out the waves. As TD's go, this makes the game a challenge. I'm not sure if the balance is quite right. On normal, it becomes increasingly difficult to land solid hits on enemies around level 30 with the lower-to-mid level weapons. And yet, the cost for the larger weapons & upgrades is a bit too steep to sacrifice quanity for quality. I don't think the larger weapons do damage proportionate with their pricing IIRC from the original.
Overall, decent, challenging, and much more attractive.