The game itself is a poorly coded version of RC racer. The graphics are poor and the controls are cumbersome. On my first lap I found out that the graphics for the walls and where the walls are don't line up.
The game lacks polish. There are many places where more information is needed. For example, range on weapons, descriptions of what upgrades do, and info on support fighters. Also, there is no information about the enemy ships.
During an incoming wave, the only thing you seem to have control over is the one-use items. This leads to the game feeling "slow" at times.
The resources that drop seem to be somewhat random. That makes it hard to have a single pre-defined strategy. You need to adapt to what kind of drops you get. Having something original in a TD game is rare. 5/5
For the survival waves, +regen equipment is paramount. Leave one guy left at the end of battles while you rest up for the next. Also, buffs stay with you from one battle to the next, so be sure to get a buff from each class.
The only hard day is day 2. After that it gets easy. And the days should be called levels, because you can replay them. Put exp into mana regen, and get in-game mana upgrades and you should have it easy.