Lots of fun overall. The upgrades come a bit too fast, had everything maxed out well before level 16. Also, I think your "survive 15 waves" achievement isn't working. Good work.
As with other comments above, game is way too slow. Started a few rounds and I'm stucking waiting around while nothing is happening. Pause button = game over is a real bummer. Don't use the pause symbol if you can't restate your game afterwards... 1/5.
Not having a permanent path on the screen nor being able to see a units range is kind of bugging me. Also, why not just increase the cost of units instead of requiring each unit be placed on a barricade?
When your guys get to the base, they completely stop attacking the opponents units... they just get crushed and you run out of cash. Feels like it needs some tweaking rather than grinding levels just to upgrade units.
Ya sorry flash is slow and unresponsive.