ya I agree

need more towers,challing monsters,beter platform

Good attempt

All the good things about this game are what you would see in a standard TD game. So really good stuff, seriously.

Improvements:
Menu
sell button, I know you know about this one
tower diversity
upgrade diversity
levels
more of a challenge, I sit typing this while playing, I haven't added any defenses since the second level and I'm still alive.
Also add something original, even with the above listed changes made this would still be a very vanilla TD game

It's getting there!

I actually would prefer this to a lot of tower defense games.

I think if you keep working on it and get the obvious glitches smoothed out you'd have yourself a more than decent game.

Cons:
-Glitches (that have been pointed out).
-Lack of a sell button when I miss click >.> (which you already mentioned you'd add in the V.5).
-Limited units (maybe another high damage one with slow fire rate?)
-No pause button.
-No music toggle or sfx toggle.
-No restart/menu type button for game over.

Pros:
-Each unit takes the same amount of space.
-Cost to gain per kill ratio is pretty well balanced.
-Units shoot "through" each other (hate when TD games have a bunch of space behind units that you can use but are ineffective because the unit in the back is blocked).
-Simple graphics (less lag! :D)

This is of course just for this version. The pro/con list is personal for the most part and is in no way exactly how this game needs to be. Just giving my opinion!

All in all it has plenty of potential, keep it up!!! ^_^

Its not super bad for a game i give it a 3/5 tho

if this is beta then its doing pretty well for a beta but dont give us a thousand to start with makes it way to easy and add a menu i dont know why people would give this a 0/5 when this is in beta wtf is wrong with you people

Average.

Though its obvious that it lacks the fun factor, this is a well-made game if your a begginer, i also noticed some bugs, like when some creature reaches the end, they start going back, not even following the road.

You've got the hardest part made already (The game mechanics), if you want to improve it by a LARGE amount, all you need to do is add a menu, which should be really easy for you to do.
Also, if you work on the graphics, add sounds and levels, you will have a complete TD game, which will have atleast a 3.3 to 3.7 score.
Dont be lazy on making the menu as beautiful as possible, with mouse-over animations on each button and sounds, put some trees, make some details on the grass, on the road, on the turrets, also, some more menancing monsters other than bubbles.