The game looks good, and plays good, but I feel like the balancing could need some work.
There is almost no reason to use anything but Archers+Barrier, since this gives you by far the best DPS for the best price and the other Towers are just too weak to matter, outside of their maxed out form, which you can only have 1 of.
In Plants vs Zombies for example, the Pea Shooter and the Ice Pea Shooter did the same damage with the same shooting speed, but you paid 75% extra for the slow.
Here the Archer dies way more damage per second compared to the Ice shooter, so the slow is now not a bonus for the extra cost, but a trade of effect on a tower that still costs you more. And a row of Archers is better at clearing the line than a row of Ice towers or a mixed row. (though the ice tower appears to do better against Walls)
The Phonix tower is even worse, again, the burn effect is not really a bonus, since the base tower itself has the lowest DPS by far, and only the Level 3 Version seems to have an AoE.
So basically as the game is now, the best strategy is always spam Archers, have 1 of each other tower to get the Level 3 Form, and thats it.
The game is still a fun thing to do to waste some time, but the balancing needs work.