The game seemed to lack a sense of urgency. As it was, I just bought all the skill upgrades and finished the game in under three 'days'. I think the overall game might have been improved with the addition of two things:
A) Start the tree at ~20% and have it slowly dying if you aren't healing it. This would add a resource balancing issue.
B) Have the skill tree be more open ended. If the player doesn't have a 'hard' cap on skills, they have to make more meaningful choices with regards to how far to push a given skill.
The controls leave a lot to be desired in a browser game. It would likely be far preferable to click and drag the mouse to orbit. Also, the content doesn't all fit on the screen at the same time, and using the scroll wheel both zooms(sometimes) and moves the browser content.
You need to add a door block. I built a wall to trap asteroids, but now have to go to the bottom of the ship to squeeze to the other side. Overall, I'd say this has some real potential. Also, you have a bug in the build screen which causes the players hp and shield to reset to 5.
Once you've accumulated the required cash, you shouldn't have to wait for the time to run out for the game to end. I bought an hour worth of extra time so I wouldn't have to worry about it while I explored the game, and now I don't want to wait for it to all run out.
A description of how the units work would go a long way to improving this games playability. It wasn't till I found out that the 'trainer'(girl) was how to generate wolves. Once I learned that, I was able to beat the first board with only moderate damage.
I'd suggest two changes:
1) Change the fire command for squadmates such that they keep firing on the target selected at the time the command is given.
2) Provide a free fire command so your support will fire at the nearest targets.
1) If you're able to stand still and not take damage for 3-4 seconds, the counters and health should reset. Either that or provide a reasonable and compelling reason not to sit and wait for the cool downs to cycle between fights.
2) It might be worth while to add multiple levels so that the jump is more useful. As it is, just jumping over the traps is unsatisfying.
Two points: 1) Once a column or row has been slid by a player, it should not be possible for the other player to 'undo' that move. This prevents the potential deadlock. 2) The AI needs to be a bit more mindful of defense. The same five moves at the start of the game always produce a win for the first player.
Change the XP so that there is a limited quantity of XP per level by either setting a max spawn or only awarding XP for the bases if you want to award skill versus persistence. Granted you'll need to increase the XP per base if you base only option.