on second examination this isn't half bad but gameplay seems a bit bland.
the main issue i see here is that its way too easy to get from your home base to the enemy's home base, and that the gameplay is kinda simple (dodge through trees, shoot, dodge again, walk in the general direction to the enemy base). The towers also have an uninterruped LOS to pretty much everywhere on the map making them slightly OP (or underpowered) and easy to camp (and camp in).
I'd suggest to have a large-ish valley separating the two camps rather than having the mountain, and then have some rock formations blocking direct LOS from one side of the canyon/valley to the other. And to make players down in the valley not easy to kill add some overhangs (ruins of some bridge? etc) and caves. Though, doing what I suggest here probably would require you to make a whole new map.
When building TDM's try to go for variety in map design. Don't have the whole area open and easy to snipe through, but also don't make everything crowded and difficult to fight in. Variety is the rule of thumb.
